Would this coin address the inevitable dump that comes after a coin reaches a exchange?
There's nothing to prevent what people choose to do with their coin. But, by design, there won't be the "early miners with a ton of coins" scenario that we've seen play out multiple times, so people won't have tons of easily acquired coins that they could just dump.
Would it be possible to track the number of non-mining transactions, and factor that into some kind of algorithm that would lower the block reward when transactions were high, and raise it when transactions were low? Within certain parameters, of course. Unbounded reward limits could lead to undesirable concentrations due to perfectly normal fluctuations in the amount of transactions that have occurred since the last adjustment.