This is very interesting
. I don't think any body type in particular is better, except for height. I don't think I've ever come across an elite female gymnast over 5'4?
Presumably muscle type will count- if you don't have fast twitch explosive power and a high muscle to weight ratio you're never going to be able to get enough height to double back, or even standing tuck, for example. So your graceful gymnasts need power, but your powerhouses also must have flexibility for the range of motion. So I doubt you'll ever find extreme examples at elite level, but rather variations on a theme.
In the UK at least the elite track seem to be leaning more and more to the graceful flexible ones. With the range and conditioning at compulsory level, and the limits on difficulty, the ones leading the field are the ones with beautiful oversplits and control. In Romania too I've heard they're raiding rhythmic clubs for future elites. So the current trend seems to be for graceful, flexible gymnasts with power second.
I do wonder how that'll work out at senior elite level though. Catherine Lyons for example, who has led the field from 8 years old and just won the 2012 british espoir (11-12 years). Beautiful, beautiful gymnast, but when you look at her scores (Vault 12.350, A-Bars 9.950, Beam 13.900, Floor, 13.900 Range 13.300) while she won the floor, beam and range (range by over 1.0), she was 2 points behind the winner on the vault, and 3 points behind on bars, not making top 10 even for either piece. Obviously I don't know if she had an off day or whatever, but I can't help thinking now the difficulty is increasing gymnasts like her might struggle with the power aspect.
Anyway. DD is a total total powerhouse, but her flexibility is naturally poor (for a gymnast) She has gone from about a foot off to just about down on all 3 in the last 6 months so she does have the ligaments that will improve with work. However she's not on the elite track because she doesn't have the split leaps and the control to hold split handstands, slow tiktoks etc.
I do sometimes wonder whether we're missing something at the early age. Having an elite track (vs the US system where everyone works the same levels) means any children that if you don't get picked up for the elite track before age 9 you're going to really struggle to get there at a later age..