I right a rant along these lines about every three months.
A hole in the Glitch design right now is the lack of reliable ongoing drivers of action. There's all kinds of things to do, but outside of quests, there's not really any reason to do them. Like, when people are like "where are moar quests?!" and "sandbox group!" those are responses to that.
In my opinion, though "moar quests" is kind of untenable (and wouldn't be really successful.) Glitch quests do a good job of running you through game mechanics so that you know that they're there. Writing "enough quests" would be a gigantic timesink on the part of the limited devs, and and wouldn't really solve anything. Quests would eventually be about the same as "donate more of the things" - a bit of churn to get more iMG.
Upgrade cards, at least for me, we a bit of a bridge on this. "What upgrades are there for me today? Okay, I'll make enough iMG for *that*" But eventually, it all comes down to "make more iMG or currants faster."
For a long time I've wanted to see official buy orders in Glitch. Basically, imagine if there were a list of what other players were willing to pay for the things you can make. I yearn to log into Glitch, check the Orders Board, and say "wow, look at the bid price for Girders (say) today!" and go about making some Girders.
Maybe they'd have the same problems that Quests and Upgrade Cards do (another grind for resources) but at least I'd feel like I was doing things for other players - that somewhere there was a player out there who was glad to be getting the thing they needed (and maybe another who'd been too slow to fill the order). I'm heartened in this conclusion because of the enjoyment I've had trading emblems to make Icons.
But vending SDBs in Towers feels like exactly the opposite direction from that. It's the auction house, but with less transparency and more hassle. You can still only *sell* and only at a particular price. The prices aren't going to be globally accessible or comparable, so there'll be much less idea *how much* to sell things for, and the popularity process that's (in my opinion) showing up in resource loops is going to be heightened in terms of selling things.
I'm dismissing with contempt the idea of a "trading channel" as a solution for finding the prices for goods. Advertised prices need to be *persistent* (like the prices in the AH) not *transient* (like chat entries in a channel).
Group Halls (as variants of Towers) might well ameliorate this somewhat. Add Buying SDBs ("This SDB wants more Meat and will pay 8 currants per, out of its 5000 currants") and a market board in the Hall, and maybe we're somewhere.