One wet/dry properly setup can help you avoid the "circus" you said that you dont want. Sump is the best you can add anything in there. I couldnt and wouldnt go back to canister filters.(IMHO). One tank one filter....Priceless
I would do a large sump... built off of a 75 gallon tank or larger.. if mechanical becomes a problem then you can always add a fluval fx5 or xp3 xp4 etc.... later on...
I suppose it can leak. If the return doesn't have a hole to break the siphon (or a check valve) it could overflow.......
If it's designed correctly you won't have issues. Canisters pose just as much risk as a wet/dry IMO. If the return line comes loose, the canister drains your tank. They can also leak from several spots.