I think it's a lot easier to just bash Hasbro for this than to look at why they are taking this approach... and this is coming from someone who has been royally pissed at Hasbro for quite a while now.
I know right off the bat that a $20 vehicle is an easier purchase for a parent now... heck, parents are more likely to pick up TWO ships for $40 than just one for $35. It's a much better value as far as they're concerned. Looking specifically at Obi Wan's ship and the Repubilc Tank, if those two were all the same ones as before, with the Republic Tank and Obi Wan ship being $30-$35, each one of us here would pass because we already have them, right? Or am I wrong?
We all know that there has been a huge slow down in product moving in this line since the prices went up, and it's affected the mid size vehicle line. The vehicles just aren't moving in the $30 range. You can walk into any store and see product from January just collecting dust, and at TRU, they are sitting on a lot of 2011 product still. The economy sucks and Hasbro is trying something different.
However, Hasbro isn't a completely innocent victim of the economy - they need to realize that a lot of blame for the Star Wars slowdown is due to their own bad moves with case assortments (which is painfully obvious with the basic figure line too). Stupid, stupid podracers have to be part of the reason for this too... those pieces of crap sucked the life out of the vehicle line in 2012.
On any note, I think it's a decent decision by Hasbro to try this out - but I do hope they still work out a way to have some vehicles out still in the "proper" scale... maybe as exclusives. For example, if K-Mart can keep the AT-ST down to $35, I think we could see new vehicles and popular repacks still for $30 - $35 here and there. Hasbro probably needs to be selective anyway because a lot of the mid size vehicle repacks aren't that sought after.
We really don't know what's in store for this line after this first wave yet - they could surprise us with some repacks that are already smaller anyway for this new $20 line... like the Snowspeeder, Cloud Car, Geonosian Starfighter, just to name a few.