SC2 doesn't suffer as much from the gas issue. However, there are a few things worth mentioning.
Without a picture at this spot I'd lose half of my readers.
The Test
I fought a fierce battle with the new Map Editor. The result isn't pretty. But it works (if you know how). I tested 56 geysir positions for all 3 races over 300 game seconds and wrote down the remaining gas for each position. A few calculations later I designed a bunch of fancy pictures in MSPaint.
The Results
The first result is that all three races mine gas at the same speed. This was not the case in SCBW.
The other results will be supported by pictures. The big blue square is your townhall. The light blue area around it is the area that cannot have any resources in it. The small colorful squares each represent the center of a geysir. A full geysir would cover an area of 3x3 squares.
Relative mining rates with 3 workers.
This picture displays the the mining rate for three workers per geysir relative to the absolute maximum mining rate. As you can see there are barely any differences. Geysirs in diagonal positions already look a bit suspicious though.
Relative mining rates with 2 workers.
Who says that you have to put three workers on gas all the time? As you can see, you can harvest with up to 79% of the maximum mining rate with only two workers. You have to be careful though, because the mining rates of some positions are much worse than others.
Mining rates with 2 workers, relative to the mining rates with 3 workers.
If we compare the mining rates with two workers to the mining rates with three workers, the results are not as bad. And in fact this is all that counts when you have to decide if you put two or three workers on a geysir. Unless you are considering using a fourth worker.
Ladder Maps
Indexing the positions.
Indexing the positions.
Before I can talk about the maps, I need a way to reference geysir positions. We start from the red square with the number 1 and go clockwise around the townhall until we reach number 56.
+ Show Spoiler [Blistering Sands] +
Top right:
52 (top), a bad position
19 (bottom), bad for two workers
Bottom left:
47 (top), bad for two workers
24 (bottom), bad for two workers
+ Show Spoiler [Desert Oasis] +
Top:
45 (top), a good position
41 (bottom), a good position
Bottom:
13 (top), a good position
17 (bottom), a good position
+ Show Spoiler [Incineration Zone] +
Left:
1 (top), a good position
30 (bottom), a good position
Bottom:
43 (left), a good position
15 (right), a good position
+ Show Spoiler [Kulas Ravine] +
Top left:
43 (top), a good position
36 (bottom), bad for two workers
Top right:
15 (top), a good position
22 (bottom), a bad position
Bottom left:
50 (top), a bad position
43 (bottom), a good position
Bottom right:
8 (top), bad for two workers
15 (bottom), a good position
+ Show Spoiler [Lost Temple] +
Left:
55 (top), a good position
31 (bottom), a good position
Top:
45 (left), a good position
13 (right), a good position
Right:
3 (top), a good position
27 (bottom), a good position
Bottom:
41 (left), a good position
17 (right), a good position
+ Show Spoiler [Metalopolis] +
Left:
38 (top), a bad position
32 (bottom), a good position
Top:
8 (top), bad for two workers
13 (bottom), a good position
Right:
4 (top), a good position
10 (bottom), a bad position
Bottom:
41 (top), a good position
36 (bottom), bad for two workers
+ Show Spoiler [Scrap Station] +
Top:
54 (top), a good position
19 (right), bad for two workers
Right:
53 (top), bad for two workers
18 (right), a good position
+ Show Spoiler [Steppes of War] +
Top:
53 (top), bad for two workers
18 (right), a good position
Bottom:
46 (left), a good position
25 (bottom), bad for two workers
Conclusion
In SC2 the Gas Issue is much less problematic than in SCBW. It still is something you might want to keep in mind, especially if you consider using less than three workers on gas. Which was my main motivation for this research; it will come in handy for a build I am currently working on.
SC2 map makers should also be aware of these results. You only have to avoid a few positions in SC2, in SCBW you had to avoid all positions except for two.