Skyrim's too hard now!
An unleveled Skyrim is not easy for a new character. Why would those dungeons still be filled with monsters & treasure?? The levels are similar to the old PermaZONES here; I recommend you give that page a read because it covers a lot of the basics.
My simple recommendation is that you play naturally: if you can't handle a dungeon, come back at a higher level.
Note that MLU has static Encounter Zones, so they scale neither up nor down.
Check out Character Creation Overhaul if you'd like better new characters

Some enemies are still level-scaled
It's possible to "perfect" the deleveling, but not worth it imo. There's not much left and the item lists still prevent Glass+ from showing up. Some level-scaling makes sense, such as with Dragons - they start at about the same time you do, so their growth in power should nearly align with yours. Most enemies found in the exterior worldspace will still level-scale (usually unchallenging). If I deleveled all the exterior spawns, it would introduce new compatibility issues without solving any real problems.

Should I still be finding Dwarven/Elven/Orcish stuff in random loot?
Yes. More than original Morrowloot, much less than Vanilla, and Dwarven items even less outside their ruins. You'll even find a few Glass or Ebony pieces from certain high-level random spawns. If you put MLU very low in your load order, your MLU patches below that, and made a Bashed Patch then you should be finding these items in the right place.

Can you patch "x" mod?
I want MLU to have a lot of patches, but I can't do everything. I prioritize patches that I want to play myself and can't promise anything else (still feel free to ask). This is why you get huge patches for Summermyst or Immersive Armors, but I randomly put one out for Mainland Stalhrim that no asked for. That's just how it plays out. Authors AsatorThundrGod, Mebantiza, and Rusey have been granted editing rights and contributed to the patches.
Check out the Community Patches page for more patches made by other users

In a nutshell, what's different from Morrowloot Special Edition?
Original Morrowloot just delevels loot and eliminates the crafting of anything Dwarven+ (in addition to all the artifacts he made). MLU does those things plus everything else in the description (note that crafting is restored with restrictions).

How does this compare with Requiem?
Requiem is a far greater mod, both technically and in scope, but the easiest way to explain it is that Requiem changes the whole flavor while MLU keeps things close to vanilla. Requiem doesn't just delevel Skyrim, it overhauls most gameplay elements. Give Requiem a try if you're interested.

Load Order and LOOT?
LOOT doesn't know where to put MLU.esp, so you'll have to make adjustments after it sorts. Weather and lighting mods can be placed below MLU safely, but anything that modifies leveled loot will need to be placed above. MLU Patches must be below MLU.esp. Don't forget about Wrye Bash!
Note that load order only matters when two files mod the same records: if there are no conflicts, load order does not matter. You can always investigate with SSEEdit, which I recommend you do with every new mod regardless of load order.

Must I start a new game?
Nope, but MLU is recommended for new or early games. The more content you've already cleared, the more hand-placements and other good stuff you might have missed out.