i see where you are coming from, however this is commonly the case with food processors- you CAN'T fill them up more than 1/2 or 2/3 if what you are processing is liquidy at all, or it will like you said ooze out the middle, etc. i guess it's good for people to be aware of this, which is common with almost all food processors, so if you want something for bigger batches you do have to get a bigger bowl.
although the product is appropriately named "mini" and appropriately priced, IMHO. I don't consider a 2-can batch of hummus "mini" by any means. I have the 7 cup cuisinart which is a good size for all but the most mini jobs, and could def handle 2 or maybe 3 cans of beans.
i have had a similar experience to yours in the past- and initially i was pretty ticked off! but then i looked at the design of the center stem and realized it should have been obvious to me that it was not intended to contain liquidy stuff above the level of the stem, it is obviously not sealed. but why can't they fix this design flaw, maybe with a taller stem piece? after all, the name is a little misleading when 4 cups really means 2 or 3. more solid chopping food isn't so much of an issue, though.