Yes, I do believe that the adoption of a universal language would be simple and fairly quick to implement. Most countries today are already speaking and/or learning the English language, therefore the rest of the world can easily jump on the band wagon and join the English speaking population too.
By using all the same language, all the people who has pride and loves their culture and languages are completely ignored. And think about it. If your language is not chosen for the 'Universal language', will you still agree with the 'Usage of Universal Language'? If you think about it and also think about your passion of keeping your country's things, then you should also definitely disagree with this.
English requires people to mark in their speech (and so typically their thoughts unless you're smart enough to notice this and gradually get yourself to use a modified form of english for your own thought processes while avoiding negative effects on communicating in official english; when you can just find a way to word things that avoids using the future tense "will") whether an event is in the future moreso than other languages.
For instance, in German you can say Morgen regnet es. English requires "It will rain tomorrow".
Read through this paper. It goes over how language can effect people's intertemporal choices. The mandatory marking of future events (use of "will" in English) leads to people ignoring future outcomes moreso than in other languages.
While it may take time for people to learn a different language we must consider the future. We should have a universal language but it should be a constructed language determined based on the best science. I'm not suggesting anything totalitarian. People should be free to use other languages but worldwide the newly constructed language should become a mandatory subject in school and the official language of diplomacy and of international organizations. People should also be educated on the effects of various languages on the mind so they can make more educated decisions on which languages to learn.
I studied and continue to study German. I find myself becoming more efficient and more concerned with how I spend my time. German culture is known for punctuality and efficiency. I admire that. Of course I'm just beginning to understand linguistics. German probably has its deficits like any language and I'm sure English has its high points. But a universal language should be constructed to carry all of the high points and avoid disadvantages.
We can not even all decide on using the metric system, so I can not imagine how we could learn a universal language. The Tower of Babel story in the Bible says it as a metaphor: that we are divided by our cultures and our words. It is a source of fighting, but we may not be able to do better.