Imho, the animation/control concept of synergies could really use some more love (much like light and heavy attacks got it in the past, i know that synergy ranges have already been tweaked to increase the possibility for conscious choices by players). However, it still feels really bad to use them and most importantly pressing the button is not 100% reliable. Thus, you often find yourself repeatedly pressing whatever button you assigned synergies too. The result can be that your character executes two or more synergies in a row. Especially banner + talons triggers this a lot, because a mag dk will combo those two skills anyway and try to place the banner as near as possible as rooted enemies.
This minor inconvenience becomes a problem when you cannot reliably abort this synergy execution (your char chain-stomping like an angry 12-year-old): Where block/bash/dodge seem to take precedence over "normal" skills and channels (or can be combined, weaved, animation cancelled, etc) - this doesn't work nearly as well for synergies. Imho it's really annoying to die in a tough fight because you want to use a particular synergy, end up using 2-3 others instead and finally die because you pseudo-cc'ed yourself in synergy animations.
I don't think such changes would have a huge impact on combat in general, but for me (and others I guess) they'd significantly improve how combat feels
Kasiia - Templar (AR46)
Kasiir Aberion - Sorc (AR38)
Dr Kastafari - Warden (~AR31)
+ many others