I'm not 100% percent sure, but I would guess that making draft mode only would require people to own more champs than are in the free rotation, further cutting down the number of people who could play. If there was only normal draft for 3s, you'd need to own some champs.
Not a huge deal, but I feel like getting more people into TT will do more in the long run. Doed that make sense?
One of the biggest BIGGEST complaints I get from friends... is that 3v3 stinks because game is balanced for 5v5 and it leads to some op champs dominating. I respond with "why not pick op champs?" and they say why play them in norms when they will be banned in ranked?
it never ends...
PLEASE DO 3v3 NORMAL DRAFT WEEKENDS a few times (and remove blind pick normal if need-be) as a present to us people that like to play normal 3v3!
(build it and they will come)
There are numourous TT draft mode normal request threads filled with these types of comments (there are probably 2 years worth of threads asking the question "why no draft mode in TT norms?" and there are probably 100's of responses like the following.
I would play 3's if there was draft mode. NO TRYNDAMMERRRREEEE
ps - if a normal draft only weekend is not possible - please try a one patch (2 week?) run of normal draft only to gauge customer response - I suspect that if you could get it in there for a weekend it might open the door to play some norm games with friends that refuse to play 3v3 based on op champs. I suspect you would see a huge increase in people trying 3v3 again if there was draft norms.
ps2 - not many people want to play ranked games in 3v3 with people who do not play 3v3 regularly - and not many people want to play ranked 3v3 without practicing in norm (but since many banned champs get picked in norm its not a realistic view of what you are going to see in ranked)
just out of curiosity can you share the data (or some roundabout estimates/ratios) that compare the queues between 3v3 norm/ranked mode vs dominion norm/draft/ranked modes?
also... just how tough is it to TRY something new in a game mode that is unloved by your general population of players?