"...and all while playing for a much worse team." -- There's no evidence that playing on a worse team increases or decreases your overall #'s.
Felton had a PER of 14.0 last year to Rafer's 13.4
Felton had a TS% of 50% to Rafer's 49.2%.
Felton had an AST-r of 30.1 and TO-r of 11.0 to Rafer's 25.5/10.4.
Felton played more minutes than Rafer last season, but they both scored 15.3ppg-per-40 minutes, so no Felton did not have a scoring advantage.
That doesn't look like a big upgrade at all.
There's also chemistry Houston has to worry about. Take Shane out of the trade and it might be doable. But Rafer+Shane makes it borderline retarded.