It seems like the controversy that accompanied GW's introduction of the 32mm bases for the Blood Angel Tactical Marines, Death Company, and Sanguinary Guard has died down a bit. I think most people recognize that nothing is forcing them to re-base and most have decided whether or not they're going to adapt the new base sizes for their army.
The largest schism was between the hobbyists and the competitive players. Although most hobbyists didn't seem eager to re-base existing models, they were generally excited about having the option of using bigger bases. The competitive players, on the other hand, were fretting that other gamers will gripe about their army having non-standard base sizes if they stay with the original 25mm bases (I would have left 40K several years ago if I had to play in such a hostile atmosphere) and complaining about possible advantages that armies on one particular base size will have against armies on another base size. Many of the latter complaints seemed to focus on the effect of size differences on base-to-base contact.
Out of curiosity, I decided to look at the actual affect of playing 25mm versus 32mm bases on close combat:
In the Abstract
If you were to ignore the weapons, limbs, etc. that typically hang off a model's base, a single round base of any given size can only come into base-to-base contact with six identical bases:
So what happens if your new Sanguinary Priest on its 32mm base is surrounded by an opponent's Astartes on their original 25mm bases? It turns out that your model will still come into true base-to-base contact with only six other bases:
Although a seventh 25mm base will obviously be able to participate in the combat, it will never actually contact the larger base in the middle.
What if your Space Marine Captain is still on a 25mm base and you're surrounded by a new Blood Angels Tactical Squad on their 32mm bases? You will end up in base-to-base contact with five Blood Angels:
A sixth model will still be involved in the combat, although it won't be in base contact with the base in the middle.
In short, the only real difference occurs when multiple models on the larger bases are in base-to-base contact with a single model on a smaller base. However, in a game that's as dependent on random dice rolls as 40K, I honestly don't believe that having one less model in direct contact would have a significant effect on the course of a game.
Let's be honest; how many assaults actually look like the figures above? When your models look like this:
you're not likely to achieve those hypothetical patterns.
Although most gamers' comments on the new base size seemed to focus on assaults, I'm more interested in what the larger bases will do to disembarking squads, especially when a 10 man squad's drop pod drifts near an enemy unit and the space for disembarking is limited. It's just as well that I'm going to keep my Tactical Marines on 25mm bases, but I still intend to field a 10 man Sternguard Squad on 32mm bases.
The Veterans might just find the battlefield to be a little bit crowded.