I've been a bit all over the place this season... I was doing a lot of mega-base in November, December then SST-type workouts in January and into February and was seeing good FTP gains, brought in more focused intensity with some VO2 or shorter intervals, more stoachastic group rides, as well as started racing in February. I raced 2-3x every weekend through March, my short-duration power went up and my threshold power somewhat stagnated and my endurance tanked, then my threshold followed. I wasn't riding nearly as much as last year but I think I came in with a lower base as well as probably overreached a bit, as well as just hit a peak and my form slid backwards a bit.
It's hard to say exactly what is working or not working for me right now though because my fitness right now is far above what it was this time last year. I was able to go out and hang on no problem in a cat 3 crit no problem (and 1/3 of a P/1/2/3 crit with some difficulty) the day after a 400 TSS day, then put in 200TSS yesterday and was riding very strong at today's "hammerfest" lunch ride.
My body seems to not respond very quickly to workouts, and my biggest gains last year were when I stopped racing as much, put in tons of volume, then tapered down once a month to race. I'm going to try that again and see if the results are repeatable...
Stochastic... group rides... really? how does that work?