As I mentioned in my first post above, I am not (and do not claim to be) an accomplished Esperantist. Nevertheless, I have been around the block, as we might say. I have viewed various proposals (rarely more than that) for conIALs (constructed international auxiliary languages). As nearly as I can tell, there are now only three which have any significant, meaningful user base -- Esperanto, Interlingua, and Ido -- among so-called WENSA speakers (*W*estern *E*urope, *N*orth and *S*outh America, *A*ustralia and New Zealand), and only Esperanto has any significant usage among native speakers of non-Indo-European languages.
Yes, there are those who come and have a fleeting, minor acquaintance with this or that conIAL, and without having mastered any of them they suppose that they, the dabblers, beginnners and amateurs, know better and can overrule a quarter century or more of actual, real world experience.
Some time ago, at the risk of seeming to blowing my own horn, I wrote an Essay "Thought on IAL Success" which is available at http://www.panix.com/~bartlett/ial.html
. In that essay, I also reference an essay by Richard Harrison with his thoughts on an "optimal" design for an international auxiliary language at http://www.rickharrison.com/language/optimal.html
. I do not always agree with Rick Harrison, but my point is specifically that it is *NOT*specifically this or that characteristic, phonological, morphological, syntactic, lexical, or otherwise, which determines the overall success of some or another conIAL.
Do I think that in terms of theoretical considerations Esperanto is "sub-optimal"? Definitely, yes, in theoretical terms I definitely consider E-o "sub-optimal." Is E-o easier to learn and use than various "natural" languages? I would say, again (in the contrary), yes, even though I as an older person have not mastered it. Does Esperanto *WORK* as a medium of human communication for whatever communicative needs people have? Again, definitely yes.
The perfect is the decided enemy of the good enough. Could E-o be improved in this way or that? In my opinion, yes. Are there ways to construct a conIAL for this and that consideration? Yes. But are any of such newcomers likely to overcome a century' and a quarter's success of Esperanto? I suspect not, no matter how much I might think that things should be otherwise.
I myself support the ideal of a constructed international auxiliary language which is not (now, at least) *anybody's* (apart from a handful of denaskoj parolantoj) home language. Considering the current juggernaut of English as an international auxiliary language -- just not a constructed one! -- I think that there are now few choices, with Esperanto (even though it is NOT my personal choice) in the lead.
Reality has a disconcerting way of messing with theoretical notions.