Speaking for Maintenance here.
Yes, classes like MFE have reduced the uniqueness of stuff like trash collecting and fixing stuff to an extent, but negligibly. Keep in mind that all these classes were made with the joint cooperation of both branches it affects.
Maintenance still has priority in that MTF has to make sure there are no maintenance available before they can do anything, the exception being if the SCP that is fixed via roll like 106 gets to their penultimate advert. This exception was, again, made with the consent of Maintenance HCMD.
I've noticed a trend with recent posts of this nature. As previous commenters pointed out, it would have been prudent to check this argument with high command of the branches you are talking about. Instead, you've essentially doomed your suggestion in terms of community support as you have command/HCMD in the mentioned branches posting -support on your suggestion.
A rework of sorts could be good, but HAS to be discussed with high command. Suggestions to change branch stuff will simply not happen without the support of that branch's HCMD. (Exceptions are stuff like OP weapons and the like).
The only problems I see between Maintenance and MTF at the moment is MTF sometimes neglects to call maintenance and simply fixes stuff. This isn't a very common issue, though. On the contrary, Maintenance's main objective being repair and maintaining containment often makes it so they respond much more actively to self breaches and broken systems than classes like MFE, as MFE is often busy with other MTF objectives.
-support