I’ve been playing a Binder in one of my DnD5 games as one side of my gestalt character (the other is Barbarian). One of the problems I’ve identified is the same as all the content that came out of 3.5’s Tome of Magic: structural design flaws.
Without going into too much detail on the other two classes introduced by that book, one had almost completely ineffective casting (apart from a couple of neat tricks), and the other became impossible to use against creatures around level 10.
Pact Magic, or Binding, had the problem of not only bizarre mechanics like the others, but even more bizarre power levels between each “Vestige” you made a pact with. Even the adaptations haven’t been able to shuck this flaw, so some options are no-brainers while others are no-brainers (the bad kind this time).
I think that trying to fix the balance between the various abilities of the Vestiges is actually a waste of time, as the fundamental mechanic behind binding needs an overhaul first. I don’t have a clear idea of what’s needed yet, but my current thoughts are as follows:
At the moment, you gain access to particular Vestiges as you level, and each Vestige has a Binding DC that you need to beat to avoid making a “poor” pact. The consequences of failing the check are that you gain one or more personality quirks dictated by the vestige you attempted to bind, and you can’t hide their physical manifestation as you normally would be able to.
From a roleplaying perspective, this would be cool, if not for the bizarre mechanical nature of it. In addition, since you have a limited number of vestiges you can bind, and can only re-bind once a day, this severely limits what kind of interactions you can have with the Vestiges you’re binding.
I can see a lot of the mechanical reasoning behind these restrictions, but they end up falling a little short of their intent. I think a better method of determining access to various powers would be something more akin to how Shadowrun handles pacts with spirits.
This would mean that you could make a binding check to secure one or more favours you could cash-in for access to powers. Failing a binding could end in some nasty side-effects, so you wouldn’t want to attempt to ask too much from too-powerful a Vestige.
The way I’ve conceptualised the agreements that are made between a Binder and a Vestige is that the Binder is offering the Vestige an opportunity to perceive and affect the world again, as normally it’s stuck inside a timeless and formless void. The entities are fundamentally insane, so a Binder’s ability to form good pacts is not really about being a good negotiator, and more about managing the Vestiges hunger.
As with most of my game design thoughts, this needs way more work before it can be folded into something. Also, my efforts might just go to creating my own brand of binding in another rpg, rather than attempting to balance it for 5th ed, as more and more I’m realising that 5th ed just isn’t my cup of tea; way too much magical post-apocalypse for my liking.