Many tracks are not a bad thing in a DAW. Classic audio engineers will never put "audio dissolves" between clips on the same track. They will move the clips to different tracks so they overlap, and then they will carefully shape the audio transition between the two clips with keyframes. Much more precise than canned transition effects. That's also how you can do it in FCP X.
If you want to do your audio mixing yourself: either do everything inside FCP X (which is perfectly possible), or only do J- and L-cuts in FCP X and do all the other audio work inside the DAW. Never mind how many tracks you get in a DAW. Audio people love to see many, many tracks. And use color tags to organize them visually.
Although FCP X XML 1.5 translates audio from FCP X to Logic better than ever before, it's always better to go through X2Pro. Because that utility creates an AAF (based on Roles), which is something all DAWs understand.
I use X2Pro (I think the correct way as it always worked well with Pro Tools), but I still get many problems with Logic Pro X. Some clips diseappear, some are out of sync, some are too short. Do you trust it 100% ?
There really shouldn't be any difference, and this has nothing to do with FCP X, ProTools or Logic. AAF is an industry standard, which means it should work the same within any application that supports it. If it doesn't, this means that the AAF created with X2Pro does not fully comply with the standard. Which would explain why the X2Pro website says that ProTools is the only officially supported workflow although people have reported X2Pro working fine with Logic, Nuendo and Pyramix.
So if you use exactly the same AAF created from within X2Pro in ProTools and in Logic and you see any difference, you should report this to the X2Pro developers. It's up to them to create a fully compliant AAF.
I understand what you say and I trust you 100%. Yet, last year for the shortfilm you know, my AAF was making tons of strange stuff in LPX, and would work really well in Pro Tools. Graeme from the X2Pro team confirmed this.
Could it be that LPX is not too accurate at importing AAF ? I would find it very surprising, but I see this kind of threads:
I think the thread you have linked to confirms what I said.
The guy had a problem with importing an AAF file created in Media Composer. That AAF did not work in Logic. But when he opened the AAF in PT and he exported a new AAF from ProTools, this AAF suddenly worked well in Logic. I think this clearly shows that Logic correctly handles an AAF coming from an application that creates fully compliant AAF files.
I can understand this. Creating a fully compliant AAF that works with any DAW is much more complex than creating an adapted AAF for one specific application. As FCP X XML is evolving vey fast, I think it's not worth for them to concentrate on anything else than ProTools (which cannot read XML).