I would use Cubase till they fixed the tempotrack issue… Or Use 5.5.2 - for drumediting it is great, just the lanes are messed up and unusable. This was fixed in 5.5.3. Well…
The drumquantize stuff is working great… but… you are talking about half a song… why not doing it just by hand?
I was and I am editing mostly by hand, even if I have to move every drumhit. When the parts are easy the quantize feature is a great time-safer, but you will come to a good result without that as well - even better because you can manually control each single hit… Half a song of a standard-rock/pop song will take maybe just 30 minutes when done by hand… 10 minutes with quanztise… 10 min = 8 min fixing some hits, 2 minutes for the other stuff. Be carefull to not have lifeless drums in the end…