That seems more like a government agency whereas arbitration is usually a privately-run system and, yes, the incentive structures are bad because often the company is paying for it. It also negates the possibility of class-action suits, which are the only reasonable way anyone can get slapped for small harms to many people.
In this case the TDS is a private, for-profit company. They are also paid for by landlords.
The difference is that the government requires that landlords use them, they don't have a choice, and I believe TDS is under contract from the govt so is incentivised to effectively implement the legislation, not to pander to landlords.
> It also negates the possibility of class-action suits, which are the only reasonable way anyone can get slapped for small harms to many people.
If the arbitration is effective then this would be unnecessary though. I'm not saying that arbitration is always, or even often good, but I don't think it's by-definition a bad idea, and I think TDS is a great example of where it can be quite pro-consumer.
Another pro-consumer idea is small-claims courts. They typically have a small fixed fee, explicitly don't require a lawyer for the claimant and have processes designed to be manageable by non-lawyers, and usually claim back the fee if the claimant wins. This would also make class-action lawsuits unnecessary.
Stepping back a bit... I think this might all be being viewed from a US-focused lens where class-action suits are the only option, small claims courts are less effective, and arbitration is near universally poorly implemented. This isn't how it needs to be though, and many countries make these concepts work fine and don't need to rely on things like class-action lawsuits (I'm not even sure we have them in the UK).
I'm less familiar with other countries' systems, of course, but, for instance, if I get ripped off for $15, it's hardly worth even taking a day off of work to go pursue that. But ripping off tens of thousands of people for $15 is hugely profitable, so there's a benefit to class action in that sense. I'm not sure how other countries approach that problem but would-be reformers here generally just want to make each person have to waste their time.