I believe ARAM dodge punishment is good enough already; 15 minutes dodge timer is almost one full match these days. Second dodge; I don't know how long that is. 30 minutes? Hour? Either one is heavy punishment. Yes, people dodge. However, even with lets say 3 dodges in row, you get to the bridge in 6-8 minutes after starting the queue process. I most often experience only one dodge, two at max before the match begins. Three is a rarely occurring scenario.
Increasing the dodge timer would not really hurt me though. I don't really dodge that often; once or twice a month I guess to avoid a really sucky team (Probably the biggest reason why some people think there is a huge ARAM only account problem; Bad teams never get to the bridge in the first place due to dodges.)