I appreciate that the development team took the time to try to find a middle ground here. I am very excited to try out this change. I enjoy dynamic active combat and while I liked that I had a tool to keep up with more developed builds that had speed tools, I did not like the painful pinky strain it took to keep up with zergers. I hope the root of the issue (speed gap) is something that can be put on the (presumably long) to-do list because not every build can budget for 1 level of barbarian or has access to the ap needed for falconry sprint boost, racial ap for leaps/wings, etc. On HC, base Korthos expeditious boots are fine, but on live servers it really doesn't let someone keep up with someone who starts level one with a quiver of alacrity/3 scoundrel lives and 16 racial ap.
Some initial thoughts from what was outlined here:
1) If the way to view how many tumble charges you have is by holding shift and you have turned experimental tumble on, it seems like it would it be easy to accidentally use a charge if you are not standing still out of combat to "check". Without having tested it out yet, it sounds potentially awkward on paper. What about considering a UI element with a toggle to show/display for those who want it (similar to the display for network connection). A player could choose to have it (or not) and put it anywhere on their screen where it would be most convenient to see at a glance without a need to queue it to check.
2) In the preview you're adding charges to a Thief Acrobat and Mobility only for testing purposes. If this design gets kept, I hope you will add similar "+1 tumble charge" options to other trees like Monk and Shadowdancer (or basically every tree that has the option for taking skill selection that increases tumble). Perhaps for trees that say +1/2/3 to "skill", "skill", Tumble, you could add to the end "Rank 3: +1 Tumble Charge" to give it the opportunity cost of a 3 AP investment. Maybe this could be taken further to eventually look at "Dance of Wind" filigrees and add a +Charge somewhere in the set bonus.
3) I really like the 95% dodge bonus for 1s portion. Reflex boost equal to skill (not ranks) is a bonus that I need to give more thought on and play with to see how useful/practical it feels. On paper the reflex portion sounds good for traps, but less so for dodging spells that don't involve reflex saves. As it stands in this preview though, I don't see much of a reason to take tumble beyond one rank. The one rank gives you access to the skill and between various additive effects (Greater Heroism, Bard Songs, Tenser's, Etc) it is not terribly difficult to be getting the rolling dives on non-Dexterity/tumble-focused characters. To that end, I would like to add another layer of "choices" to character building with this tumble change: "For every #ranks in tumble, +1 tumble charge". This puts a hard cap on how many charges you could feasibly acquire in this fashion, but gives the option to do so at the cost of investing skill points into tumble. I think it works out when you consider that skill points and where characters spend them is an equivalent to training or specializing in a skill in the DnD setting. This way the Thief Acrobats, Ninja Spies, and Swashbucklers could be running around with 5 or 6 dodges (fitting for the class themes) while the Heavy Armor users/less skillpoint-heavy classes couldn't get that many charges and would have to "give up" other skill opportunities to get more.