The number of real time electronic transactions is virtually guaranteed to increase. This is not only a big problem now, it's becoming a bigger problem over time. I consider the unwillingness of the bitcoin network to increase blocksize to be a critical flaw.

Edit: The problem is not 100mb is too small for the future. The problem is that just like we cannot go from 1mb to 100mb today, we would have no ability to go from 100mb to 1000mb when needed.