Exactly this. Vote with your wallet. If you think the DLC is over-priced don't buy it, although I would like to see the specifics on price adjustment by region. I think it would be interesting
So would I, as the price adjustment's made per region seem to ignore the current conversion of local currency to the $ value and price each region differently. Oh and just in case anyone thinks that local tax or thing's like that make the DLC $25 in Australia compared to $20 in America I'm sorry but your wrong on that. Australia is currently having an inquiry as to why Downloaded Digital Media is sold at a higher price here than elsewhere and that also reflects in the price in the shops, Skyrim was $89 on Steam at release, same price in the shops compared to $50? American and the Aussie $ was and still is stronger than the American $???
BTW: Playing the DLC inclusive within your Main Game playing does 'feel' like it adds far more than it really does, so to fill out a new run through the DLC is worth getting.
Bug wise with starting a new game with Dawnguard I have yet to see a Dawnguard related bug or issue, there has been one main game oddity but that's about it?