We are 3 for 3 getting a patio table when we requested it. Two of them were great seats for viewing Illuminations, one was not a good spot (though, people with the best table inexplicably got up and left 5 minutes before Illuminations, and we moved to their table).
Our reservation was for the 7:15-7:30 time frame. Last ADR is at 8:00. If you have an ADR close to 8, then you will get the last tables left for the night, so you probably will get an indoor table- but still ask for patio! (though, as said above, if you have indoor seating, you can go to the private viewing area, which is a GREAT view, and not crowded at all - a CM invited us there as

when DD lost a tooth as we were entering EPCOT). 7:15-7:30 ADRs are more likely to get the patio, but you will have to wait longer for your table, more likely than not.
After Illuminations, they are also in NO RUSH to kick you out. Just sit back and relax while the masses leave the park. We get up to leave around 9:45. We also ask to have our desserts brought to the table after Illuminations.
With the last ADRs being at 8:00, if you have a 7:15 ADR or later, you will be the last party at your particular table for the night, so no worries about preventing your server from helping another party, and earning another tip for the night - nor inconveniencing other guests.