That's fine with me. My impression is that infiltrators are expensive glass cannons that take a long time to make, and people are trying to get around the "expensive" part as well as the "long time" part.
If you add low-risk, low reward options for infiltrators, then it would need to increase your skills slower than at the academy. Otherwise nobody would use the academy. (Or you can have a skill cap as you suggested.) I don't think that would address the complaint though. The complaint seems to be that the whole process is taking too long, in addition to being too risky.
Less required training time, less gold investment, less risk and lower damage outputs. Therefore, we cut on the long and boring process of how long it takes before an infil can actually do something without being certain of being captured, all while reducing the damage he can do to keep everything balanced.
I'd also favour changing the subclass name to "saboteur". Infiltrator suggests more ninja-like action with big booms and everything. But really, what we've been gearing towards for some time now is more towards plausible deniability, which sits in much better with small acts of sabotage than with huge missions of extreme havoc.
I cannot think of an alternative that would be fair to the other classes. Again, infiltrators can force me to skip my turn. That better come with some significant risk. And with the new wound system, a single successful attack can disable a noble for days.
Or, more often than not, your wound will do nothing but cause you to lose 2 hours or so from your time pool as you insta-heal at turn change... Tweaks to make it easier in regions without militia/allied troops and much harder in regions with a lot of both would make it both realistic and a more balanced, though, in a context where training times are cut.
