Well I do hope that SE can at least show us more tooltips on our stats and accurate percentage boost for every Skill Speed, Crit Rate and Det points we boosted.

Regarding to Skill Speed, I agree that you need a very high amount of stats for this to actually show its difference and uses. When I run above 450 skill speed, I can clearly see the damage I am dealing and the speed my TP gets drained real fast.

Regarding to Crit Rate, I agree that you also need this to be particularly high to actually give a reasonable critical hit frequency. Example when I run at 415 crit rate, the critical hit landing is just too few, compared to when I ran it above 470 and I see lots of my hits getting critical hits.

Regarding to Determination, since Crit Rate and Skill Speed just require so much boost just to show its effect, that narrows down to upgrading Determination gives a boost to your raw damage. However, I tested on a few level 49 mob just to see the difference of determination, I realized that there is still a fluctuation to the damage you deal in every hit but overall around 9 determination of stats can give you a difference in every hit.