Most of what you point out must be put in perspective.
I consider paint chips and non fitting pieces inevitable in this hobby, sooner or later they happen.
The leaning issues were limited to like 10 Black Widow pieces. On both accounts, what's really important is how the company comes through and solves the issues - not with a simple "sorry we are out of replacements", like SS seems to be doing more and more.
Delays are there, obviously, but still their production deadlines have been either in line with the competition or shorter if compared to the rest of the industry. Again, I could lose hours pointing out how many SS pieces have been delayed and delayed and delayed again for ridicolous amounts of time.
I also think/hope that they (and any other company) don't start production until they have 100% green light by the licensor, for example the Disney thing didn't impact Magneto that was already green lighted, but slowed down Phoenix's approval, so I'm pretty sure that those 4 statues and the diorama wouldn't have made it with quicker production times. And here again we could discuss that there are MANY characters that Sideshow has never done in ten years, hard to blame XM if they take longer than expected to make them.
All in all, I'd say that people are more "forgiving" to XM because XM has yet something to be forgiven, really.
Now, when XM starts to deny replacements, delay pieces for 10+ months, cancelling projects that have been going on for years and then put them back on sale with an increased ES, shipping pieces with wide and consistent QC issues, bumping the prices of 30$ every 2-3 months... well, they'll have their share of s--t raining on them, that's sure. Until them, they're good to go.