I can’t see grid penalties staying beyond this season in their current form: I don’t think there’s anyone who doesn’t think they’re totally inappropriate as a response to mechanical issues. I’m not sure more engines is the right answer, and it goes against the objectives of cutting costs and levelling the playing field, but something like constructor points penalties might be.
As for the engine regs, dropping the MGU-H should help reliability, but I’m a little ambivalent about the bigger MGU-K. It still feels a little Wacky Races to have what is effectively an overtake button, even if the use of it becomes part of the driving skill. But I suppose DRS hasn’t killed off wheel-to-wheel action, so it’ll probably be fine; and the MGU-K seems like useful technology to develop for road cars, which the MGU-H doesn’t.
Mind you, 2018 looks like my last season of watching F1 anyway, as I’m not going to pay Rupert Murdoch for the privilege. Hey ho.