Thanks everyone for your valuable feedback's. They help a lot. I will return with more details and screen shots, but quickly this is what we face now.
1. Developer has developer machine and all development activities happens here and code is moved to test as XPO only.
2. Consultants play with module level parameters both in DEV & TEST.
3. They would also be playing with Parameter changes at module level (this is the case 99%) of the time and at times play with DIXF as well which is totally unknown to developer at this time.
4. Next time when developer export an XPO that works perfectly fine in DEV, it fails in TEST.
5. Most time test consultants do not recall what all they tried. Even if we are able to figure out and turn OFF that feature or change back to what it was in original, the added code wont be removed.
Quick example.
1. We moved some customization that involves changes in VendTrans table fro DEV to TEST. All works great in DEV, Compiled, CIL, etc.
2. Code along with TABLE moved to TEST.
3. TEST compile failed.
4. Some testing or parameter ennoblement (or could even be DIXF testing) added a CFMParameters table in our DEV and added code in multiple places automatically, one example is in Table VendTrans, table method chkVendTransReorg. DEV has a Boolean variable reading from CFMParameter table and in TEST this table is not available (which by itself may be OK?).
DEV Code (Please see CFM parameters)

TEST Code snippet (CFM parameter code line is missing & TEST do not have CFMParameter table).

But when i move my VendTrans changes (for another customziatons) to TEST, this CFM code also gets moved to TEST (obviously), but remember i still do not know that a table CFMParameter was created automatically by AX in DEV. Lack of this table in TEST fails compiling of VendTrans table.
This to me is a big problem. Eager to hear from you all. (there are many other examples that occurred in our platform, but this is one of them)
Also, we do not prefer model store export from DEV to TEST just because DEV has lot of miscellaneous and partial projects that we dont want to clutter in TEST. We only moved tested and certified changes from DEV to TEST always.