This may be somewhat opinion based, but I don't think that wobble is negative-sounding in and of itself. I think it is fun and silly, in a good way - and it seems to strike the right tone for a web tool, as these often do have silly names (such as 'Pyjamas' or 'Mustache').
Positive meanings of wobble are found in the wobbling of a jelly, or a musical wobble board - and musician Jah Wobble chose it as a name that "people would never forget".
I would think that calling a software tool 'wobble' would only be negative if the tool starts to get a reputation for being unreliable - but of course you are going to make sure that doesn't happen, aren't you?