connectng CD player directly to amp, good or bad?

NO, it's not always necessary, whether it will be better is a question that cannot be answered in general though. It will critically depend on whether your cdp is a good match in electrical terms with your amp and, of course, the individual as well as relative quality of your cdp, amp AND the pre-amp you intend to use. I would avoid the direct connection if the volume control is in the digital domain, though (unless you go Wadia, phew, narrowly escaped stoning there).

Your consideration on going for first class cdp and amp now and, perhaps, adding a pre-amp later looks optimal to me. Remember you also save the immediate cost of one more IC and one more PC. And it's not only a consideration of cost, but also an interesting adventure in audiophilia, I would have thought (I am experimenting presently with a Ancient Audio Lektor V fed directly into Kharma Matrix MP 150)

I bet those sales reps all had the ideal pre-amp to sell to you, huh?

In some situations the direct connection of CDP to amp will give better resolution of fine details. Some consider this to be a more pure approach.

The preamp system will likely give better dynamic performance with more slam and impact.

Those are generalities which may not apply to every system.

Try it and see, if you get a pre you can always sell if you don't need it and it will be fun to learn the differences and pros/cons in YOUR system!

You will usually give up some convenience like no additional inputs, and most likely polarity control. Polarity can be resolved by inserting an inexpensive XO like dBX or Behringer. Both have individual polarity control for bass, mids, and highes, as well as Left and Right channels. I prefer the Behringer CX3410 because it also has a sub output. Most of the time this is where the polrity is out.

The Raysonic 168 and 228 have an outstanding balanced variable tube outs.