[RunawayEngineer]

I think that Bottom Stacking is a great way for teams to get a lot of bang for their buck in actuations. 13" of vertical travel is much easier to accomplish reliably than reaching up 6 1/2" - both have the same upper limit for tower height potential due to the rules.
Top Stacking will be essential for big scoring - since it gives you much more freedom to build on the Stacks of other robots/add more than 1 Tote at a time.
I don't think that a Bottom Stacker will be topping the ranks (assuming it doesn't have other tricks up its sleeve) - but it's a slow and steady strategy that could be valuable.