The original 500-700 Series had a 3 ring rosette and dot fretmarkers like the 300/400 Series. In the 90's, the switch was made to Abalone and the fretmarkers were more intricate. In 01 the 500 and 700s had a Koa rosette with Rosewood binding, then reverted to an Abalone Rosette in 07 when the Acoustic Series rolled out.
Recently the 700s and 500s lost the Abalone and gone to Ivoroid, in an aesthetic interpretation of guitars that were built 40 years prior to Taylor's existence. All wood appointments are on the Koa Series and although it's not Ablam and ZipFlex, it's wood 'bling'. Some like it and other that preferred the appointment of the 11 models will have to adapt to find NOS/pre-owned stock.
For the most part, the LTDs in 09 began moving away from Abalone rosettes/purfling and MOP inlays. I suspect that there is no additional materials cost in wood appointments, but the labor is more intensive, as binding has to be pre-bent, just as the sides are and they don't seem to want to just stay in-place as much as non-hardwood binding after they're glued.
Personally, I don't see Taylors as being over-adorned to the point of being 'over-the-top' and the aesthetics throughout the line in 10 are the ones I liked the most. Those days are over, but that's ok. The guitar that sounds and plays 'the best' to me is what I look for and everything else falls into place (with the only true deal-breaker being if I can't afford the $ tag).
