Its perfectly okay. I went through a painstaking time separating my hubs a few weeks ago. I now have 3 accounts containing hubs of separate interests. I was told that having specific hub niches would be beneficial to your overall hub status in search engines. I am currently seeing much better results with traffic and earnings with 2 of my accounts. In fact, I have earned more in the past few weeks than I had earned for months. Doing this also motivates me to write more and to be more active in the hub community.
So try specializing before you write too many hubs as you will have to prepare to unpublish and rewrite your current hubs. If you have less than 10 hubs you could probably rewrite and split them up easily. But if you have more hubs its best to continue with your current account and create additional ones for future hubs.