Quote Originally Posted by sayaijin View Post
I really like Zhorn's suggestions from the other thread, especially the one about making it similar to BB / GFM that it is a spell that requires an attack.Then you add scaling dice to the attack roll.
Daww, I enjoy my posts being noticed
Quote Originally Posted by sayaijin View Post
My only question is why not also add the same scaling dice to the damage roll since it would compete with BB / GFB?
Additional damage isn't including because of the power-creep concern. This point has been brought up in the true strike discussion many times in the past, often by people far smarter than I am, but the general principle there's a base level of power that you shouldn't exceed too easily as to avoid making you change the best choice in ALL scenarios. The more power you add, to keep in line with the other options available at the same level there should be some cost or restriction that stops it being the best in all conditions.
Take Green Flame-Blade and Booming Blade, both are stronger than a regular attack, but costing an action makes then less versatile than the Extra Attack feature. You can attack multiple times, or just once for a bigger hit.
Adding damage on top of True Strike is making it even stronger than that, even with dropping in die size, it is still the superior choice in the matter. You are essentially making the attacking weapon an equivalent of a +1d6 Magic Weapon at a cantrip level (note the spell for Magic weapon is a 2nd level spell for a +1), and it only gets more OP at higher levels if you include level scaling.
It's a big allure of homebrew to keep adding +pluses, but to keep the design balanced you need to look at what the other options are at that power level, what the cost is for other things that grant more power, and draw your line in the ground as your "do not pass this" marker.

At the cantrip level (ie: Action cost, no spell slots) you can have ONE of: +damage or +accuracy or +extra attack. Only one. Any more than that and you are in spell slot territory or should be relying on a higher level class feature to achieve.