Once block rewards are halved, I guess the price will probably almost double in quite a short time (multipools will basically stop mining DOGE, until buyers buy out enough DOGE for it to be most profitable again, which means the price will be almost 2x higher). This should happen in about 47 days - but perhaps people will speculate on the rise, buying DOGE in advance earlier, driving the price to double even before the reward halving
.
Until then, I guess the price will be probably quite stable - the market volumes are quite large, so unless someone buys or sells really huge quantity of DOGE, the steady inflow of coin from multi-miners won't allow the price to rise or fall much (price rises -> more multipools will join. Price falls -> less multipools, less doge on the market -> price rises again somewhere close to previous levels) from the "average of best scrypt coins when converting mining output to BTC".