I think the biggest beef about this new army interface is that the flexibility of troop training has basically been hamstrung.
Since we're probably not going to get any relief in the smaller gem-boost department, I think that a sensible compromise (which I believe would be within the spirit of the new method) is to allow one "simultaneous" slot for each barracks type you have built.
The first single troop of the elixir type would be queued in the first available slot, and each subsequent one would get it's own cozy spot until you reach the max # of barracks. After which they would be queued as shown in the mock-up below. Swap and drop as needed like shown in the video.
Same should be true for spells (1 slot each).
(ignore multipliers in the highlighted slots... troops would be x1)
http://i85.photobucket.com/albums/k6...ps3nqpd5bl.png
The "give back" on this might be to increase training times accordingly so that they are relatively the same (although I think they should remain as planned for the update lol), and this will allow folks to have greater training flexibility while keeping the "linear" approach and forcing us to "gem 'em all" if we want to boost.