<Insert various quotes here but I am lazy.>
Penalizing successful teams doesn't reduce track delta. That should be obvious. Unless it drives them out of the series. It does tend to cause good teams to behave poorly, however, which can be hilarious but also relatively dangerous if that's the sort of thing you are worried about.
I've actually raced Spec Miatas in enduros with GT1 (Trans Am) cars. And prototypes. It isn't that bad, honestly.
Class C and B cars being bumped is, in my opinion, a problem. It should not be emulated in class A. But it is impossible to know if a team won in class despite the car being slow and shitty or because it was improperly classed. I mean it is impossible under the current ruleset without doing lap time analysis and other shit that just won't happen. And no, I don't think changing the rules to define the classes is a good idea. Also, as far as I know the auto-reclassing isn't a rule, it is just a thing that started happening at some point.
And here's where my point was missed: winning is its own reward, but being _given_ a win is no reward at all.
Class X was the ultimate example of demeaning competition at the top. By placing cars in an exhibition class Lemons was saying "yeah, show up and run, but you aren't racing anymore and we won't even try to enforce the rules where you are concerned". No competition means no racing. No racing means that racers won't be interested. Ask Alex why he left.
Not only does that ruin the fun for the teams in question, it diminishes it for the teams that would otherwise be competing against them. I was pissed when Eyesore got Xed because it took them out of competition. Yeah, you could pretend that they were still contending for overall or whatever, but that isn't how psychology works.
What's the motive for moving the overall winners out of competition, either through laps or reclassing? How does that improve the series for anyone? Makes for a better "show"? Nobody is watching. The only thing I can think of is, and this was mentioned above, is that it gives other teams a "chance". At a meaningless win. No participation ribbons for me, thanks. I'd rather place second on the track in a heads-up race than get a P1 because a better team was arbitrarily penalized out of contention. I would wager that many who feel otherwise are the same folks who will cheat to win, and why help those guys out?
There are already race series where a person can show up and run and win a championship due to lack of competition. The racing world doesn't need another venue for easy wins.