Well that mix has definitely been done for the small/mid-budget RPGs, and it works well. The Shadowruns and Wasteland 2 come to mind.
However, it’s been totally absent in big-budget RPGs, which is unfortunate. I think part of that is that there’s so few big-budget RPG developers nowadays. CDPR and Bethesda, both of which are unlikely to swerve from their real-time combat. Maybe Bioware, if the next Dragon Age is a megahit and they try a turn-based spinoff or something? Nintendo with Pokemon. Square, if their TB games overperform and their real-time games underperform–problem is, that’s been happening for a while but they can’t seem to get the message.