I suppose it's fair warning to continually repeat your key points for every person who happens along to ask about Tax Deeds, but the same could be said for repeating "a fool and their money....". I did enjoy the long list of pitfalls though (e.g. environmental hazards)
Tax Deeds are offer huge opportunities for gains and in most counties you can get into these things for relatively low money (compared to buying property at retail). To me, work is work. I'd rather spend the effort researching these than retail priced opportunities that tie up 10x more money.
Even a newbie at tax deed investing would quickly (instantly) realize before putting $1 on the table that there are no disclosures or previews. That would become obvious when the auction starts and ends without such things occurring. Nevermind the warnings and disclaimers that are well displayed on county bidding information pages.
The "title defect" (the need for quiet title action) is something that I would think anyone getting into this would budget in as part of each transaction. That's what I intend to do anyway. You want title insurance? Ever want to sell the property as a "regular" sale - better budget for a quiet title action and initiate it ASAP then.
I don't think Adverse Possession is something that needs to be worried about in cases where you can inspect and protect the property before and after the sale. If you see the neighbors crap all over the lot, then perhaps that's something to be concerned with. But it's far more likely that the tax sale is one of many legal actions occurring with the property and the it's well vacated with no trespassing signs already posted. I've looked at a handful coming up for auction in my area and this is 100% the case.
I wouldn't call getting a deed from a county tax authority a defect exactly. You're in the absolute best and highest priority seat for the title with a MONSTER of an agency in your corner for the transaction. Remember - the taxing agency has and exercises their power to completely obliterate the validity of bank mortgages during the sale process - and that taxing agency is essentially part of your "team", since you are their client/customer in the sale. That's just nuts in the grand scheme of things. The taxing agencies definitely aren't the business of luring in new "suckers" for these sales.
If nobody does anything (during quite title process), you win. If anybody does anything, you still, more than likely, win. Where were these people during the YEARS that the taxing authority was trying to find them. I don't see judges being very sympathetic here, as they would be fighting against a system that they are part of.