Cheers, but how about Soft attack and softness. 3ARM/1AC brings some solid bonus for attacking soft targets. 2MOT/2TD seems to focus more on hardattack and seems more vunrable against soft units.
You can't have it all.
When using TDs in this way, you are giving up some extra soft attack upfront for a 30% increase (or more, depending on leaders) in overall combat efficiency. It's trade off, but one that I think is worth it in 90% of circumstances. Furthermore, it means that every one of these divisions doesn't give a damn about enemy armor. Even though I hate MOT for most situations (not enough like MECH to be awesome, motorized enough to get terrain penalties that INF doesn't get), it's less of a strain on logistics and costs less IC. Works just fine in open terrain.
If you are really looking for lots of soft attack, you would want to go with MECH/TD, but that's more expensive and strains logistics more. You could also do something like HARM/SPART, but that's even more expensive, uses more fuel and is slower.
But if I am just worried about SA and not speed or hardness, I just go with 2xINF, 2xARTY anyway. Plenty of SA for the cost and uses no fuel. But it's slow, has low toughness, and is 100% soft. Oh, and it hates certain terrain thanks to having a lot of ARTY.