Hey sorry to take so long to get back to this thread. Definitely some great point made and the discussion is very helpful so thanks every one! There's way too much here (that's a good thing) to respond to everyone's points individually so I thought I'd make some general points and let the convo run with it.
- I think I left out some critical info... Yeah I have a 28/42 bail out that I do use on occasion, but that's on the trails/newb offroad stuff I ride.... the kinda hills where you have to be careful if you sit normally in the saddle you'll roll over backwards but if you move your weight too far forward you lose rear traction, not a chance theres a paved road where I would be riding a road bike that's that steep. Realistically I could lose my one maybe two largest cogs on my current bike if I'm sticking to only roads around the GF's place.
- BTW I'm not riding 'to' the GF's place. It's a longish distance relationship so if I'm riding there, the ride is all around there. I looked it up as best I could and theres a nearly 2km long hill that's 6% and a couple that are a bit under 1km around 8%, and some very short stints aproaching 12%. I know not what you mountain guys deal with but for me it definitely takes some work though doable.
- In the last couple days I ditched the mediocre/crappy shock fork my bike came with for a rigid carbon one, along with a carbon handle bar and seat post. Real life measured #'s it shaved 1.8kg (or nearly 4lbs) off the bike. Holy hell what a difference! I rode a familiar route and felt like I was flying. The data off the garmin said I was only ~9% faster but wow it felt better than that. Anyway, point to that is I'm very optimistic how much more efficient a proper road bike is going to be.
- I made the comment before I crunched some numbers, so yeah I'm not really going to get a close ratio cassette. I haven't put it into any calculators yet but anything beyond the 11-32 does look a bit awkward with the steps. I think based on what's been said and the significant gain I've had on my bike by dropping a bit of baggage I'll go with the 50/34 rings and 11-32 cassette.
I do have a question though and it might be a bigger deal here. With the Deore XT drivetrain I have now the front chainrings shift easily as smooth as jumping a cog in the back. I shift the rings often more so just to keep a straighter chain line since it's so smooth. It's nitpicky but I hate any noise from the drivetrain, if I can hear it - it's too loud. The shifters also have a great feature that they'll drop two cogs in the back and drop from the big to small chain ring, it's great for getting set up for climbing because it approximately maintains the ratio I'm riding in but now I'm in the small chainring. The shift is so seamless I've had to look down between my legs to make sure it actually happened in case I didn't hear it. It sounds from the discussion some avoid shifting rings, do road rings not shift as smooth?