But, IMHO there's more to a succesfull language/system than the sum of the parts.
Almost every language has its strong points which others lack. What I mean is that you don't necessarily get a better language by combining the strong points.
One major success factor is the evolution of a language. It has to adapt to its users - and Esperanto IMHO doesn't do that.
I'm comfortable using English as the lingua franca in the technical world. I most often prefer it to my mother tongue German for clarity and simplicity.
However I'm also aware that English has its roots (at least partly) in old germannic languages (Disclaimer: I'm no expert here - Input appreciated.) and thus is also based on other languages.
Well, from this point on I would repeat myself, as I just became aware of, but you get my point ;-)