Why TP Waiving has to be removed.
I think just about everyone disagrees with my suggestion to remove TP Waiving. For the combo system to make any significant changes and to become even slightly more flexible, the TP Waiving must be removed. All the restrictions on which weapon skills work together, and how many you can combine are a result of TP Waiving.

For example, if you wanted the possibility to freely combine skills, yet keep the TP Waiving, there has to be a restriction on the number of skills you could combine; otherwise, you would be able to essentially weaponskill forever (the only limitation would be cooldowns). This may be unrelated, but I also see cooldowns on weapon skills as an incredible design flaw.

In addition to the number of skills, the TP Waiving either forces the player to only use their best weapon skills, (when you can get a free WS, why choose the 500TP Weaponskill when you can use the 3000TP Weapon skill). So that incentive is already created by the players and the mechanic itself; but, the developers have decided to also force us into certain combos as well. Instead of us being able to figure out the best 3 WS to form our combos, they did it for us. (Another restriction).

So, in these two ways, the TP Waiving is an absolute restriction on the players and the developers. Although it may seem great getting free weapon skills, the balances that have to be made to allow such behavior are extremely restricting. These restrictions limit choices, and as I have said.. choices = strategy, and strategy adds depth to combat. Essentially, if you do not remove the TP waiving, you cannot have the freedom to make your own combos.

This is why I listed TP waiving as one of the most important and the worst mechanic of the combo system DESPITE knowing a lot of people think it is awesome, Because who doesn't like free stuff? But things are never really free.

I think we can all agree that the current cost of a combo is the cost of the first weapon skill; usually 1000 to 1500 TP. Because you are able to get more skills out of less TP, and therefore more damage out of less TP, they reduced the speed in which TP is accumulated for all classes.

Just incase a community rep is reading, if I were to pass along anything to the designers, it would be this following paragraph (Everything up unto this point is merely reasoning/justification - I find it hard to argue for the current system because it is so limiting, and because this is really simple changes - maybe not from a technical sense but at least conceptually extremely simple):

My suggestion is just simply this: Remove the TP Waiving first. As a result, the total cost of a certain combo increases to upwards of 5500TP. This is way over the top, so certain weapon skills need to be reduced back to what they were originally. So something now that was 1000 > 1500 > 3000 = 5500 would change to 500 > 1000 > 2000 = 3500. Because TP waiving is removed, you would be allowed to combine these weapon skills in ANY ORDER you wished. so 1 > 2 > 3 would be the best, but let's say a monster is almost dead, you could simply just do 2 > 3 right away, or 1 > 3. The real cost of the Weapon skill is the time it takes to acquire the TP. You wouldn't have to do any real balancing changes, if you simply increase the speed in which TP accumulated. So, by removing the TP waiving, and reducing TP costs, and increasing TP accumulation... skills could stay essentially the same... but you would have the option of combining them in whichever order you wanted. This = MORE FREEDOM, MORE CHOICES, MORE STRATEGY.