I finally put in MrSpeakers alpha pads on the DT770. It's a really nice combinations. It fits like it was meant for DT770 almost a perfect fit. It does change the sound signature. For one the isolation became much better. The recessed mids has been raised quite significantly. and the bass has been tightened and pushed to the middle of sound stage. Comport level is also much better the alpha pads is like a soft pillow for your headphone. However It does heats up a bit more on prolonged use compared to the velour but not a large margin.
The only minus I can think of is smaller sound stage compared to the velour pads. But I guess it's understandable because velour vs leather pads. definitely worth the change or an alternative pads if you want to have a different sound signature to the regular velour pads.