Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Not sure so much an issue, but perhaps you'll not be leveraging the maximum potential of your 3750s' network resiliency.
First, if possible, MEC between your 3750s. Second, if your licensing supports it, go ahead and run L3 in your drawing's left 3750 stack. If you do, you won't need to MEC between stacks but insure the two L3 links are on different stack members. Convert the L2 trunk to L3. (If you keep it L2 trunk it will work, but you set yourself up for unicast flooding.)
If you don't run drawing's left 3750 stack as L2, the left L3 link can logically connect to your MDF stack. Again, make the L2 trunk between the stacks MEC, if that's not possible, insure that trunk is on a different MDF stack member from the other L3 link connected to the MDF stack.
Basically, a multi-member stack will keep running with failure of a single unit, but what's the path redundancy to/from other units if that happens? This is why I'm recommending MEC or L3 links on different stack members.
