Powering my matched 7.1 set of Triangle Comete es's the SC-07 had a distinct improvement over my previous receiver an Integra 5.3. The most obvious were its ability to play louder with the absence of fatigue and a much more palpable midrange. All this prior to running room correction which the Integra lacked. Powering my very reveling Avalon Eidolons showed me the receivers limits mostly in staging width and depth and none of the brightnes you've described.
Switching amplifiers do have a slightly unique presentation that isn't for everyone. I would guess that the SC-07 may be showing you the shortcomings of the speakers your using. Other than hearing your speakers in large consumer electronics stores powered by an array of receivers all wired into a switching console it's difficult to offer a reasonable assessment of their quality. Even so I'd suggest a speaker upgrade before giving up on the SC-07.
Switching amplifiers do have a slightly unique presentation that isn't for everyone. I would guess that the SC-07 may be showing you the shortcomings of the speakers your using. Other than hearing your speakers in large consumer electronics stores powered by an array of receivers all wired into a switching console it's difficult to offer a reasonable assessment of their quality. Even so I'd suggest a speaker upgrade before giving up on the SC-07.