For a while I was doing one of those big 2-base gasless mass marine pushes; Day advertised a 6rax one with a CC first build; I found myself preferring a 1 rax expand into 5 rax marine push (slightly weaker push, but it telegraphs itself less and feels safer). That killed a lot of people outright, and put me in a decent position for a lot of other matches, but since Day did that daily, it feels as though it isn't especially successful. I get the impression that that build depended a lot on people not knowing how to deal with it yet. The point of the push is to force the Protoss to delay their tech because they're spending the gas on stalkers and sentries, but it seemed like I was delaying my own tech further by waiting so long to take gas.
So I've been 2-raxing. In all match-ups. Not a gasless 2-rax, 11/12 or 12/14 or anything. Just regular 12 barracks, geyser 14-ish, and second barracks after orbital. First rax goes reactor, second rax goes tech lab, and begins researching combat shield immediately, Then I pull guys out of gas, expand, and try to put on some pressure with the combat shield marines.
It's an interesting difference. I've been 1-rax expanding for so long, that it feels strange to have gas as soon as that. My opponents seem uncertain how to respond (this is at platinum level, mind you); protosses usually scout the gas and have to go robo, which makes the guessing game easier at least. Zergs who do a Spanishiwa-type no gas expand have no response for the combat shield marines. This seems like a reasonable alternative to hellions for denying creep and third base; I can push the creep back to whatever spine crawler wall they have, and if they used any evo chambers to wall against hellions, I can simply snipe those off with the marines. Note that I'm sure this would be considerably less successful against a Zerg that took earlier gas, since they would probably have zergling speed up by then, but I'm fairly certain that it still does me good to put the pressure on. Push forward, kill creep tumors, force zerglings, and then retreat before the zergling swarm can surround the marines and kill them.
TvT also goes interesting places. Most plat Terrans don't go barracks-heavy as an opening; everything is either 1 rax expo, early marine tank medivac push, or cloak banshee. The 1-rax expo guys have some trouble holding the combat shield marines; they generally rely on a bunker for defense, and I can easily either kill the marines outside the bunker and retreat, or run around the bunker on most maps. All marine trades feel satisfying because even if I lose the push, I kill more marines than I lose because of combat shield. The tank push guys aren't too terrible, either; if I scout gas, I can pump marauders instead or marines out of the tech lab barracks, and generally hold the tank push just by having enough units.
TvP, the inspiration for this opening, is the most interesting. There's a curious trend of nexus first forge defenses lately, and while I know academically that is not supposed to be viable PvT, I'm still working out how to punish it. Massing as many marauders out of 2 rax as possible works unless they build 4 or 5 cannons at the natural anticipating the push; getting metagamed is frustrating, but I understand doing a build like that you probably get all-ined fairly often. Rushing to medivacs to circumvent the cannons seems to come out too late; by then the 2-base economy is up and there's a million stalkers waiting for me. The most promising line seems to be a smaller, earlier 2-rax push with 5-6 SCVs pulled. So far that has successfully broken 2 cannon defenses, and I think it might even break 3. It's way too early for them to have more than that, and they definitely can't have warpgate yet so a swell of zealots or something doesn't seem like an issue.
Assuming they're not Nexus firsting, the match is more creative. I expand and push with conc shell marauders and combat shield marines, and that pretty effectively shuts down most greedy expands. Since he scouted gas he generally goes robo, which usually means he'll go the colossi route. After the first push ends and I have an expo up, I generally add on more barracks and head for medivacs (add factory while push moves out), so if he starts massing up colossi I can fairly easily put another starport on that reactor from the first barracks, and get out as many vikings as I need. If he dashes for templar anyway, then hopefully the first push will scout something to that effect, and I try to put down ghost tech just before taking a third base anyway.
Here's the biggest issue. Current wisdom is that I have to press him during this period and do some decent damage, or else with both players left unmolested, toss will crush in the late game. That's all fine and well, but the result is that there's no pressure on him to actually move out or pressure me in any way. He just has to hold my first push, then proceed to expand. My follow-up push is generally when medivacs first come out. If he has colossi out by then, that push has to wait another minute or so until vikings can arrive. If he has templar, its probably another two minutes before ghost tech completes, moebius reactor is researched, and ghosts actually appear on field. During this time, he proceeds to take a third base and sit safely behind his colossi or templar. Most importantly, because I have to dash for medivacs to be able to put on pressure, dash for vikings or ghosts to be able to engage without getting AoE'd to oblivion, I have precisely no gas for upgrades. I suspect he could win the next engagement even without colossi or templar, just by rushing upgrades and flooding zealots.
After that the opening ceases to matter in all match-ups. The most important legacy of the opening is that I am gas-starved in all match-ups for the midgame, since the second base came up about a minute later (maybe a minute and a half, I forget the exact timing for when a 1rax expo finishes). TvZ I proceed to 3-base, 3-factory many rax, with quadruple upgrades (double bio, double mech). Quadruple upgrades seems a little much, but when infestor broodlord comes around, I can't seem to make heads or tails of it unless I have either 3-3 thors, a fleet of vikings with all his infestors somehow out of position, or a massive base advantage. 3-3 thors are most reliable. TvT I try for more tanks, again with quadruple upgrades, because bio is so much stronger tank support than hellions, and medivac drops are the best way I can find to control expansions. Ultimately it comes down to positioning the tank line to take bases and shut down his, which I'd like to consider one of my strengths. And in TvP, if everything goes well, I shut down his colossus army quickly, bring in ghosts and land appropriate EMPs to ensure I don't lose everything I have to a single storm, and then when the big engagement comes, those leftover vikings from before snipe all observers, and I proceed to walk the cloak ghosts forward and EMP his whole army pre-engagement. This does not happen if his templar arrive to defend before I can ghost, or if he simply out-upgrades me and crushes me with zealots, or if his stalkers and colossi manage to kill my viking fleet and stomp everything I have, or if he lands that single storm and everything dies.
Ordinarily I'd write all this in my Starcraft notebook, but I decided to post it here. If anyone wants to read and/or comment, go for it. If you think it's boring or too long or too low-level or anything else, feel free to ignore this blog entirely.
+ Show Spoiler +