Well If POP/PUI decides to Sanction Unlimited like how Modified is currently, they need to set it up like how Magic: The Gathering does it with their Type 1 formats for Legacy, Vintage, and Extended which in this case for the Pokemon TCG would be all wrapped together in one format or divide Unlimited into 3 seperate formats.
First of all in Unlimited there's only a few banned cards with no erratas instead, so there should be a Banned/Errata list exclusively for the Unlimited format only. It shouldn't effect Modified due to set rotations similiar to that of Standard Type 2 in Magic.
If POP/PUI did a Banned/Errata list or the Banned/Restricted list like in Magic for Pokemon's Unlimited format that'd be great, If they ban cards they should stay banned, If restricted keep it that way for reasons that's understandable to the players for a fair and balanced TCG and has been playtested by the game's R&D team, that's also one of my pet peeve's with Yu-Gi-Oh! is that they flip-flop with what cards to keep in or out and they sometimes don't know when to make up their own minds about it either.
The way UDE did their Banned/Errata List in Marvel/DC Vs. System wasn't that bad IMO (which is how Pokemon should do Unlimited IMO besides Magic), they had very good reasons for what actions they did and though sometimes it may have backfired it was all for the best to appease the playerbase. Checking on power creep issue's and keeping up with the Golden Age format (Type 1 in Vs.) is also vital and important as well to which should be implied to what POP/PUI should do with Unlimited in the Pokemon TCG If it becomes a Sanctioned Tournament format like Modified.
But yeah I agree with qnetykz, Magic also in a sense has the same problems in Casual with Mono Blue Control decks (Countermagic) decks and how they're unfun to play against and the problem arose again in Standard with Black/Blue Faerie decks when Lorwyn block was still legal in Standard and it got to the point where Wizards of the Coast is hating Blue up to this day even in sets they release so far.
I'm not saying that Magic: The Gathering is busted in terms of Casual, sometimes ingenuity and decks tend to go a bit too far and every deck has flaws depending on what you're playing against. You learn from your losses and adapt to how you're going to beat the deck you're having problems against and I'm glad that WoTC have been making cards for other colors to help get around Blue Control decks even though they're dead in Standard currently.
Yu-Gi-Oh!'s problem and the reason why IMO they flip-flop on Banned/Restricted cards or more or less could of avoided it is If the game was designed to have a resource system and by the time things got crazy with the Chaos decks and Yata-Garasu there was way too much power creep and Konami/UDE didn't know how to handle it but what I'm trying to say is If the game was designed as good as Magic: The Gathering it probably would've never got to the problems it had in the first place.
Pokemon and Magic are different cause they have a resource system to keep the games balanced, power creep is inevitable in the majority of TCG's but If handled properly it can survive it and prosper. Both Magic and Pokemon have already proven it with the right responsibility by the R&D team to keep the games as balanced and enjoyable as possible.
Sorry If I went a bit off topic...