I'm pretty sure I had enough PP from general gem drops by the time I hit t6 to pay for that final mandatory sink. I don't think I've ever set up a bazaar trader on this server, sadly. I don't box 6+ toons though, so purchasing large numbers of those tokens for t6 armor was never an issue. I can see it being expensive for people who box a group or more, but that's the price you pay for boxing so many imho

Then again I did all my AA'ing in LDoN so I always had plenty of plat on hand. I had always wished there were more plat sinks so that platinum became more of a commodity and prices on higher end gear would lower.
I do like your idea on non-mandatory plat sinks though. The buff-saving thing sounds fishy coding wise, but I'd love to see illusion pots that last while zoning. High stat/low duration foods would also be awesome, maybe some heroics? 80k for a coth orb is pretty darn low, especially considering the ghall clicky sells from vendor for 160? Coth orb would likely fetch at least twice that, unless it had a long CD like 1/hour. More TS mats is very welcome idea. Air infused spring water please!
Keep in mind that platinum is not very difficult to come by. Average per normal LDoN clear is 5kpp. Most t5+ non-donored players can clear one in 10 minutes and be on to the next one. That's 20 minutes give or take worth of farming for a token for a piece of T6 armor. Not that horrible. 30 minutes for a Powerful Temper for 2.0. Etc.
Drop the HoH symbols another 2-3k and you'll see platinum start to empty out of those banks that hold many millions of platinum. It will take a while, but as those players and their guildmates decide to make more alts they'll opt for the quick way out and buy their T8 points rather than spend a month slaughtering easy trash in a laggy zone. Less platinum in the hands of the big boys = increased value of platinum serverwide as they sell off attuneable items they don't need in order to pay for the t8+ stuffs they do need.
The issue isn't that there are too many plat sinks and that they are too big, it's that there are zero plat sinks after t6. Period. There's nothing to spend platinum on to make it useful at all. Unless the GMs have something devious planned for VT....