Some one enlighten me on what it would take for these coins to inflate in relative value against BTC in the future. More public interest? More exchange acceptance?
Is it even possible? Are the current exchange ratios really undervalued, or are they stable the way they are?
You're not thinking this through clearly. The simple answer is supply and demand. In a situation where the supply of crypto-currencies is growing rapidly and in fact INFINITE and the market demand is very much FINITE the picture is clear: The value of any particular crypto-currency in this process of unlimited creation will tend towards ZERO.
For a crypto-currency to resist this highly probable outcome and maintain a non-zero value it needs to offer something unique of value to the market that others do not. For Bitcoin the value proposition is obvious: "First Mover, Network Effect, Largest Market Cap, Widest adoption". For Litecoin the value proposition is still there, though less clear "History/Longevity, Faster Confirmations, Harder to dominate through ASICs".
For third place and beyond the value proposition gets even murkier.
Peercoin: Proof of stake means moar secure!
Namecoin: For storing uncensored name/value pairs
Primecoin: Useful for finding prime numbers
Quark: Lots of nested Hashes means moar secure!
DogeCoin: It's funny (until people get bored with cute dog jokes)
etc...
With hundreds and then thousands of these coming online over the next year, how much demand or even attention will people give to these? Answer: Not enough to make their values > Zero. Unless your favorite crypto is in the top 10, or more like top 3, I wouldn't expect much from its price other than short bursts caused by occasional pump and dump attempts.