Saddle:
To look at an example (although I'm sure others will finds reasons to not use this as a good eaxmple), At least 4 Derby runners this year fit the no-development profile you bring up. Greater Good, Spanish Chestnut, Closing Argument and Giacomo. Go figure. 2 apparantly hit their non-developing ceiling at least in the short term and X'd, One ran a 2 point new top and was good enough to get 2nd, and one improved 4 points to win. I understand your (our) dilemma and here are some questions I ask myself when figuring out what to do with these types. First, I look for reasons I might expect improvement. I'll consider the trainer stats: What is the trainer's win % and ROI over the last 90 days? Has there been a trainer change since the last race and how well does the new trainer do 1x trainer change? Is there an equiptment or jockey change and what are the trainers stats with the change(s) Do the sire stats point to something like a possible improvement with maturation? Second, I'll look for potential reasons to excuse the non-development so far like troubled trips, unfavorable post positions, off tracks, a long layoff or the opposite racing too many times to close together or even recent health issues. Third, I ask, will I be getting what I consider is good value when I decide to take a shot with a runner that has not developed but, as you mention in your example appears competitive with the rest of the field. This is by no means all inclusive and I hope others will have more to add.
Regards, Phil