I've said this earlier, but I'm not 'optimal' fully indoors but close. I can do most things, granted 8% worse but power wise its the same on the road. There are little nuances in training you get outside, especially riding with others, and my tolerance for pain goes up outside. Of course that small difference I get is really big in a race. I'm still scheduled to do BWR in November, and there's no way I can just go from trainer to that. At some point I'm going to have to start riding in the dirt, as those skills are atrocious.
topflightpro I watch a ton of TV on Trainerroad as well. I'm actually amazed how many series I've been through. Has to be roughly 30-40 since last fall.