I don't completely agree. More cells does give more surface area, kind of. You still have the cells all stuck together and heat dissipating from the top, bottom, and sides. You really can't count the surface area that mates to another cell as heat dissipation surface. The heat is just going to transfer from one cell to another, and heat the pack up more. Also, if you had for instance, an 8000mAh 2s and an 8000mAh 2s2p, then you have one pack with 2 4000mAh cells, and one pack with 4 2000 mAh cells. In all likelihood, the 2000mAh cells are about half the size of the 4000mAh cells. In this case, 4 2000mAh cells don't have much more surface area than 2 4000mAh cells. Regardless of anything, I feel the only surface area you can count as far as heat dissipation, will be the outside surfaces of the completed pack. This is likely to be similar between two packs of the same capacity.

As Glassdoctor said, the balancing effect of multi cell packs is an interesting thought. In practice it won't really work that way. If the cells are stored for a long period, perhaps they will all bleed to the same voltage, but that does not change whether one cell in the pack discharges faster than the rest of the cells. Fewer cells in a pack will equate to having statistically less chance of a bad cell in that pack. If both the cells are matched well in a 1p pack, and you treat the pack correctly, maintaining good balance between the cells should not be a problem for the life of the pack.

The last point I can think of, is that if you take two packs of the same discharge and capacity ratings but one is a 1p and the other a 2p, the 1p pack with only 2 cells and 2 solder joints should have a lower overall resistance as compared to the 2p pack with 4 cells and additional solder joints and wiring. This should result in slightly better efficiency and less heat.

lol, anyway, i've always gone for the pack with fewer cells when it's an option.

J.