I admit that I know little about Esperanto, but I agree that it might just add a burden instead of solving a problem.
English has its advantages too, I agree that imperialism is one of the reasons it is so spread, but it is also because of the simplicity of the language which makes it an easy language to learn (for a functional level, I mean). Grammar in English is very simple, if you compare it to many other languages.
I think that sometimes you have to use what's already there, that is, if English is the international language now, instead of trying to bring up another language (that won't go global unless there is imposition of some sort), you can learn that language and do your best with it. Learning a language is about practice, so once you learn the basics, by "doing your best with it" you can learn even more over time. I think of it as using the enemy's energy in our benefit, instead of wasting our energy to try to impose something in the natural flow of the world just because we don't like English.
Besides that, while we can have the many advantages coming from know the international language (namely, access to information and networking globally), you have the access to understand the language of the empire itself, which definitively gives you a plus. Moreover, I think that you don't loose your language and your culture just because you learn another language, at least, that's my experience. On the contrary, by learning different languages you can expand your understanding of the world without loosing what you have learnt so far.
Finally, I wanted to point out that, even though it is true that being English the international language, it gives advantages to native speakers in a way, from my experience as a teacher, and for what I know about international examinations, people from around the world can achieve a proficiency English level while native speakers can't just because they're not interested. So, one thing is colloquial English and the use of English by most of the people, they've got a vocabulary and structure according to their use of the language; but, for academic English, everyone (natives and nonnatives) need to learn the vocabulary and other structures that are used in that context. I work with Cambridge examinations, for example, and the University lives out of foreigners who study there, and there are many examples of foreigners who speak "English" better than the average natives themselves...
By the way, English is a language that is spoken mostly by nonnatives, especially Indians (there are more Indians who speak English than "native" English speakers), and most Indians still speak their own language and keep their own culture throughout their lives. Similarly, Chinese people live around the world and they learn the local language but most of them keep close to their culture and traditions in some way, and most of them keep their language, of course.
So instead of trying to create something unnatural, which would be very difficult to make it flow naturally/organically, I repeat, we can use what's already there and use our energy for other things...
Fwiw...