I disagree: I think that the proportional distribution with PTS and BTC is enough to get people to donate to AGS, regardless of the price of protoshares, and it also provides donors with some nice benefits.
The way I look at it from a long term perspective, if you send bitcoin into AGS, you're more than likely getting a ridiculously good deal on shares of future 3I DACs for a (relatively) common currency. If you're sending PTS to AGS, it's kind of like a bond in that you're giving up your liquidity for a larger piece of the social contract pie (at least, as long as the donation threshold remains under 5000 PTS.)
Besides, if you add too much complexity to the rollout, it's going to drive away AGS donations.
Edit: Also, if you allocate more AGS shares, then you're effectively making everybody else suffer an inflation tax that was not clearly spelled out in the original terms.