Unless I'm misunderstanding, I think the OP's meaning is that you tell the DM three different character concepts you'd like to play, he compares the ones every suggested, then tells you which one to make (and you keep it all secret from each other).
I'm not seeing how that should be a problem, especially since presumably the DM will guarantee niche protection, and with a group that has played together for 13 years will probably do a pretty good job of putting together concepts he thinks the party will enjoy.
I did something even more unusual (and possibly something people could validly object to) for my Savage Kings theme adventure (15 sessions home brew adventure). I told them that they would be playing the rulers of lands of more savage cultures/races rather than more traditional characters. We met so we could brainstorm character concepts, but I didn't let them know which races they would be playing. I think I had them put together ability scores without racial adjustments, and tell me what class they wanted to play. I then had us come up with character concepts without too much specificity. One player wanted an militaristic amazon style archer ranger, another wanted a Romanesque fighter, another wanted a young bard, one wanted a cleric with a nordic feel, and one wanted a totem barbarian. I believe I had them come up with names also. I smiled because I knew this would work out great.
I think I told each spellcaster (possibly in private) what level of caster they would be, and asked them to select spells they wanted. Then I told them I'd have to alter their characters a bit and get sheets to them. In response to some questions I told them there was the equivalent of some level adjustment ECL stuff that would be going on. That was basically all they knew.
When we started up the first session, we began with scenes of each character "on their throne" or otherwise in their base of power, while I presented things going on to give them the flavor. I tried to drag out the uncertainty as long as I could, and I'm not even sure everyone had figured it out by the end of the introductory scenes, but the reveal was that each character was a giant: the barbarian was a hill giant chieftain, the nordic cleric was a frost giant jarl, the Romanesque fighter was the cloud giant emperor, the militaristic amazon was the fire giant queen (the archer ranger was a stretch, but the backstory and culture she described worked great for fire giants), and the young bard was the regent of the storm giants.
They also didn't realize that it was set tens of thousands of years before my primary campaign timeline, when dwarves were slaves of the fire giants, elves were barely heard of, and the lesser races like humanoids didn't even exist. They got to adventure through the mythic age with floating earthburgs and Dr. Seuss styled mountains as they gathered their forces for a mighty battle with an army of dragons.
It was awesome. But it was also known to be a limited length theme adventure rather than a new campaign.
