I just want to say that up to the point of taking control of the console (and making the ultimate decision) i loved every damn second of this game. It is without doubt up there with ME2, even better in some respects.
Also, while i dont like the fact that the strange VI was some kid, i enjoyed the ideas of the Reapers as the 'order' to the chaos (instead of evil monsters) and the implications of destroying/controlling them.
Now onto the endings... I picked the Synthesis Ending as i thought it was the most interesting option. I thought that my ending fit it perfectly; the normandy being stranded on some planet and coming out all hybrid-y was awesome as it sort of signaled the start of a completely different existence. Sure a bit more closure would be nice, but i enjoyed that ending FOR that choice.
With the other two endings, however, i thought it was stupid how they landed on the planet and the same stuff occurred. It simply doesnt fit and it makes all the endings the exact goddamn same.
For the Synthesis ending, leave it pretty much as is. I like the idea of life essentially resetting into this strange hybrid mode. Add some more interesting closure but i enjoyed it.
For the Destruction ending, I'm torn. Either make it a conventional 'we did it' ending, including closure on how all of the main characters will spend the future (maybe flashes of the Javik or whatever his name is enjoying the peace with Liara while writing his book and you can think of the other ones). The other option is to make it destroy the mass relays (as the Reapers and mass relays are both reaper technology). The only problem is this makes it a 'bad' ending as life is all stranded and screwed up so i'm not sure about that. Maybe make it so all systems with mass relays are destroyed (due to the impact of the explosion of the relay) and a new cycle begins though without the presence of the Reapers. Then, as an epilogue, cut to the advanced species of the cycle creating synthetic life or something, insinuating the child's prophecy that the new cycle would simply create chaos all over again.
For the Control ending, keep the mass relays and everything intact (since youre not destroying ANYTHING). This should be a conventional ending too (especially if the destruction ending is my mass relay option instead of my conventional one). I can't really think of anything interesting here but there you go, get creative. I think this ending should keep the universe and all of the lifeforms the most 'intact' since it is an ending which simply controls the reapers.
Interesting ideas, Bioware, but you did not successfully play out each ending differently, and logically enough. For the Synthesis ending it was good, but the others, not so much.
However, i would like to thank you for one of the most epic and interesting trilogies of all time and i hope that you pull through on the ending (free) DLC to remedy this unfortunate flaw.