I'd go ahead and do what you plan to do, becuase it's hard to say whether something is balanced or not without seeing it in action and testing it. I'd make you game prototype and leave it open to be altered as you need. THe whole point of a prototype is to test it and fix what needs to be fixed. It' would be even easier to alter if you kept a set of constants that you can find easily.

Such as:

const int DexDivide = 2;...TP = (Dexterity / DexDivide);...

So in the even you find that only halfing the dexterity isn't enough, you could change DexDivide to be equal to 3 instead, and make TP be equal to one third of the Dexterity.

Similarily, you could keep constants for TP usage in attacking and moving.

const int TP_MovePenalty = 2;const int TP_AttackPenalty = 3;...if(-Player attacks-){   TP - TP_AttackPenalty;}if(-Player moves-){   TP - TP_MovePenalty;}...

In any case, you must test the game to be certain it is balanced. If you really need to know before you start programming it, you could draw a grid on a pice of paper, and act it out. It might give you some insight into it.

It doesn't sound very balanced in the sense that each attribute is equally useful. Seems Dex is partially the way to go no matter the kind of character; Strength won't do you any good when doing magickry and Mana won't help you crushing skulls, but Dex makes you more efficient at both, and pretty much anything else combat-wise, I'd suppose.

Tho like ToohrVyk said, it can be it's balanced, depending on other stuff. Might be tricky tho. Eg. if you're some jack-of-all-trades-esque character, Dex will suddenly become more useful, as focusing on other stats will make you specialize, while dex makes you better at everything, while a more specialized character might find dex to be about as useful as some attribute of his choice.

Depends on a lot of other stuff, and a lot of "if that's what you're going for" things and such. I'm sure it could work. Tho if it was I making something, I'd probably go for a more constant number of time points and instead let relevant stats affect speed somehow (either by letting stats affect the tp cost of different actions, how much stuff is performed per action (eg if your dex is 10 or more you get to strike twice per attack of some swashbucklery kind, while high strength might allow for more strikes with really huge hammers etc) or a combination of both).

You would have to make unused TP not carry over between rounds, or else limit the amount that can carry over. Otherwise the system will be broken.

Otherwise a player could hide and skip a whole bunch of turns to accumulate TP. Once they had enough up their sleeve, they could run out and kill every opponent without retribution.

on the game ive been working on characters get a set number of free moves and after that the tp/movent cost rises exponentially, theres also a maximum movement cap and max tp cap and characters are only allowed one attack per round but have multiple moves with diffrent tp cost and damage

Yeah, but your opponent would have just wasted three turns walking around looking for you, or getting into a position where they could attack you. Only they wont have the extra TP up their sleeve.

So being able so save up TP makes sense if you want ambush and hiding to be an effective strategy, less so if you don't.

This reminds me a lot of Fallout. In that game you had Action points which depended on your dexterity, but it was well balanced and other attributes were as important as dexterity.
Back to the topic, I think that how Fallout handled leftover action points is the best way to do it. In this system any APs you had left when you end your turn would add to your armor class (dodge modifier) during the enemy's turn, and when it was your turn again that AC bonus was gone and you were back to normal. This system made leftover APs useful and prevented exploitation of the system.