At normal listening spl if you want to hear noticeable sound quality improvements, the best way to achieve that is to stock up and stick to high quality media such as good recordings in sacd, Telarc, Chesky CD, HD flacs etc and upgrade your speakers. I know people tend to turn to amps because it is an easy upgrade, and can be more affordable, but that route is only cost effective if you had entry level pre pro/amps. The problem is, your RXV1900 is a solid performer among mid range AVR's,such that most people won't be able to pick it out from high end gear in a properly conducted comparison tests, when they are not subject to placebo effects from hearsay.
The Rotel you bought is a good move as it will certainly give you a bit more headroom but the biggest benefit may be in providing you with a wider range of speakers to upgraded to as you no longer have to limit yourself to east to drive speakers. Back to the pre pro, if you need the latest features go for it but for sound quality, don't expect miracle unless you are prepared to welcome yourself into the Placebo world, but that actually is not hard to do at all.