compact double advice

[VeloVT]

My cx bike that I'm using as a commuter (Bianchi Axis) has a super-low triple on it (48/38/28). The shifting is a bit slow, I NEVER use the granny ring, and I've been finding lately that I always want a bigger gear than I have downhill, and now, frequently on flats too, even when I'm carrying a backpack.

It has a huge mtb rear cluster, I believe it's something like 11/34 (9sp).

So, I do enjoy having lower gears than on my roadbike. Commuting, I usually have an extra 20-30 lbs in my backpack, and there's one hill that's about a mile long with one somewhat steep section (not killer, but maybe 7-8&#37. There's also an outside chance I might someday want to try cx racing, so I'd want a setup that wouldn't rule that out. Plus, although I have road tires on it now, I'll be putting cross tires back on it when the weather gets worse, and that slows me down a little.

I'm considering switching to a compact double. Since the bike has 105, and I believe the shifters are double/triple compatible, I'd only have to change the cranks and maybe the front derailleur (but I think that would be more a weight saver than a functional necessity -- and I'm not super weight conscious with this bike). I'm hoping this would give me a little additional high-gear power, make the shifting a bit quicker, save a little weight, while preserving some lower gears for riding up hills with a load.

Do you have any advice? Does this sound like a good idea? I'm a little worried about the jump from 50t to 34t -- do those of you with compact cranks find there's a range where you have trouble finding the right gear, the big ring is too big but the 34 ring is too easy? Or not? Any advice would be appreciated.

Thanks for your help!