No, I haven't. All I did was replay the ending a few times, eventually just having my Femshep shot by Marauder Shields. I really loved ME3, except for the ending. But most choices you made, in either one of the games, have their resolution way before the end of ME3. This might sound like an advantage, but it isn't.. As it turns out, as far as I can tell, I made all the right choices with my main playthrough, meaning things turn out the way I want to in ME3. So anything I do different will probably just have an adverse effect. I have a few other characters, even started playing ME1 with two new characters. I actually quit because some of the conversations I had were very different, just by choosing a single different option. That is what makes these games so great, but when it comes right down to it, it doesn't matter and that just makes me feel sad. Even though choosing different options will change some things and will at least be somewhat enjoyable, having my Shepard interact with different characters more, perhaps try another one with a different love interest, in the end what I am playing for is the resolution of the story. In ME2, I put in a lot of time to get the perfect ending of the final mission. I even went back after starting ME3 to tweak it further, because I had accidentally gotten Tali killed (major whoopsie) and hadn't noticed. I don't think anyone told me and then I saw the memorial and went: ah, man.. Not Tali! Even though I didn't romance her, I like her character too much and it was well worth going back and saving her again.
Basically, I've done a large share of the things I can do with my characters in ME1, ME2 and ME3, without going the other way (I have an almost perfect Paragon, with just a smidge of renegade). But, I didn't choose Paragon without a reason and besides, what's the point? Paragon, or Renegade, most often you end up with the same result for different reasons. The times that the results are different, you end up pissing people off who would have been useful later on. Is there anyone you can threaten into cooperating that you couldn't charm? Or else it -really- doesn't matter, such as saving the collector base and the human reaper. (WTF? Seems like a huge deal to me!) With vastly different endings, as I've outlined elsewhere, the games become almost infintely replayable. Then it would be well worth investing the time to play through with several other characters. Wouldn't it be heartbreaking to discover that you can save Earth, only at the expense of Shepards life or that of a teammate or perhaps even your love interest? Unless you are willing to let an entire race die? Forcing you to make hard choices? Unfortunately, that isn't possible yet. Worst, we don't even know what really happens at the end. So what am I playing for? Just to be ready when the new content comes out? What if it's not good enough? Here's to hoping Bioware will really and properly fix this, but unless they planned this from the start and just move their timetable forward a bit (not so much as to result in less quality) I don't think they can deliver on what we are hoping for. If Indoctrination Theory is wrong and they just put that in for whatever reason, then it would be a massive undertaking to do it all over again and I don't see how they could do it. But I'm hoping that they will deliver. They sure have shown that they can write a great storyline, write interesting characters and make our choices matter. I just don't understand why they didn't follow through on that for ME3. If it was a money problem, why not just be upfront about it? If it was anything else, then I seriously do not understand why they would alienate their fanbase like this.
So, in short, in the end I think it is not just about the journey for me, it is also, to a large degree, about the destination.