RTwP doesn't qualify as a "genre" either literally or in principle.
In the case of the former, technically RTwP is a straightforward mechanical and/or presentational choice. You might as well classify isometric viewpoints or toolbars with lots of buttons on them as "genres" as well.
In the case of the latter, that being the principle of the thing, RTwP is an abomination—that, and a true bastardization—deserving no recognition or classification other than as an abomination and bastardization. Absolutely every cRPG on record featuring RTwP would have been improved had a turn-based system been used instead, and that includes Darklands. RTwP has a legitimate place in certain strategy games (Homeworld, Sim City) and as a sort of "helper system" in simple, usually first-person console action games with slightly complex character ability systems (Parasite Eve, Mass Effect, etc.), but that's as far as it goes. In practice, RTwP is a wholly different animal in those kinds of games, too.
In the context of complex and especially party-based cRPGs, the pressure to implement RTwP or even real-time combat systems was born from developer/publisher desire to make role-playing games more ACSHUNY! and VISCERAL! and REALISTIC!, thereby expanding the games' target audience to include impatient, retarded teenagers. This is decline seen in its purest form, one of the originals, an antediluvian beast so crafty and guileful that many Codexers have been hookwinked into nostalgia for it.
Don't be fooled: RTwP, better known by its true name PLAYERS WANT VISCERAL ACSHUN!, is right up there with its two companions: one being the ludicrous claim that 3D graphics are superior, and the other being the demand for voiceovers and CINEMATICS.