It's a subjective manner, but for me it has more cars that appeal to me than The crew, NFS, Driveclub and AC. Granted a lot of these aren't simulation (hence the road car bias).
How the car list appeals to you is a subjective matter. The diversity and amount of number-padding isn't.
Strictly speaking, The Crew has a fair amount of race cars. Not as many as GT Sport, and they're all designed by the developer as well... but that shouldn't be an issue if you're okay with PD-designed ones. Actually, if we counted all the build variations in The Crew, I imagine we'd end up well into the triple digits. Surely we can't count a Monster Truck-spec Fiat 500 as the same as the road car!
I'm not enamoured by AC's car list, but it's a pretty decent one. It has more diversity (Group C cars, some old DTM, open-wheelers, vintage and modern F1 cars), and has more Porsches available than any other game out right now (at least until the beginning of October). AC goes pretty dupe-heavy in the Lotus list, but outside of that, I think it's a pretty good one.
Everything in GT Sport is either a road car, a Vision GT, or fit into one of the four PD-designed categories. Oh, and the BMW i3 — it's odd that's an X-class car, right? I'm excited to toss it around the 'Ring, though.
It certainly has a worse car list than PCARS 2 and a much worse one that FM7. Does it bother me now? No. But if they take their time with the DLC then I'd be grabbing my pitchfork.
See, that raises a whole other question. If the team has managed 150 cars in (at least) four years of development, how long will it take to hit that 500 goal? The only way I can see that happening is bringing back all the GT6 Premiums untouched. But if that's the approach, one would have to wonder why it wasn't already done.
Just shows how poorly managed this franchise is now...everything about GT now is one big question mark and puzzling decisions....
I wouldn't say poorly managed: the move to GT Sport's class-structured, less-diverse car list was undoubtedly a very thought-out decision. As ever with these sorts of things, you can't please everyone. Just look around the forums: some folks welcome the change, while others hope for a more traditional GT approach. Had the latter been taken, I'm sure we'd be seeing folks asking for a more class-oriented structure. Them's the breaks.
Also, don't double-post: that's what the Edit and +Quote buttons are for.