I doubt that.
As I said, I'm more and more convinced that Gunn was a political firing more than anything else. His fervent anti-Trump tweeting pissed off the upper echelon too much. The speed at which he was fired just tells me that this was in the works for a while. I really haven't seen people talking about this but let me explain why this was likely planned.
First off, the only comparable firing is that of Roseanne with regards to speed. However, what's important to remember about Roseanne is that she was known for her controversial jokes and tweets before they decided to pick her up for revival. Yet, Disney decided to plow forward believing she would tone down once under the network TV thumb, she didn't. As a result, she got in trouble for various tweets which made the rounds, yet ABC/Disney did nothing regarding any of these tweets. Or rather they did nothing publicly. When she finally made her "inexcusable" tweet the first season had already finished and aired, season 2 hadn't even been written yet, and the cast were on break. In fact, the day she tweeted that shit out was the first day the writing crew returned to start crafting the second season. Why is this important? Because, it's all about business. Cutting Roseanne out now meant a bare minimal loss, the first season was over and they hadn't spent any precious time or resources developing a second season. Of course, we now know that ABC actually tried to salvage the situation and get Roseanne to apologize before deciding to cancel the show (read here:
https://money.cnn.com/2018/05/29/media/abc-disney-roseanne-barr/index.html). But, likely due to her resistant behavior and fears she'd likely do it again they dropped her "quick." Naturally, the plans to drop her if she acted up had been likely been ironed out many months before hand. After all, she is under contract and you can't just fire a big name star like that unless you've perused through their contract carefully and insured that all your bases are covered such that you don't end up in litigation or having to pay them some large severance fee.
Let's switch to James Gunn now. James is one of Marvel's big name directors now, intricately linked to the Guardians franchise. And, working on Vol. 3. But clearly not everyone was happy with his anti-Trump tweeting. His rapid firing is even more impressive not just because of how quick it was, but because of how this "controversy" started. These old tweets weren't brought up by Gunn himself, they were militantly searched for and dredged back up by Mike Cernovich and other alt-right cretins. And, unlike Roseanne they were not being picked up by major networks who quickly assembled their talking heads to discuss whether or not Gunn should be fired bringing even more attention to the debacle. No, this was something started on Twitter by alt-right leaders on late Thursday and that stayed on Twitter that whole time. The larger public did not even know about these tweets until after he was fired, which naturally drew the attention of everyone to these tweets and what happened. What this means is that Disney was under no general pressure to fire Gunn. What this also means is that Disney pays close attention to what goes on, on Twitter, even "niche" alt-right circles. They saw these dredged up old tweets that they know he apologized for in the past and decided to immediately fire him. But, why fire him so fast? Remember, even Roseanne got a call to try and diffuse the situation and possibly see a path forward. Plus, remember you can't just fire someone like Gunn, there are many layers you have to go through and consider first.
What do you mean? Remember, a big name like Gunn directing multi-million dollar franchise films for a mega-corporation like Disney is going to be under contract. And, that contract is going to spell out what he can and cannot be fired for without triggering some sort of pay out. So, before Gunn gets fired you've got to assemble your lawyers, find his contract, and search through it analyzing whether or not the tweets are sufficient cause for a firing without triggering any sort of payday or legal cause of action on Gunn's part. Second, Gunn is knee-deep in production on one of their big tent-pole films, in fact he's just apparently finished the first draft of the Vol. 3 script. That means you also need to call up Feige and Marvel and figure out what firing Gunn will do to the production schedule of Vol. 3 and the MCU as a whole. Now, they don't HAVE to do this, but it simply makes business sense, unless Disney is run by a bunch of buffoons that are completely fine screwing up production schedules of their major money making franchise. Once they've got an idea of how such a firing will impact production they can go ahead and make a better decision about whether to fire him. Keep in mind that Gunn isn't just the director of Guardians, he is the creative behind the whole process. What that means is that when you are considering firing him you also have to consider the fact that you might have to throw out all his work. As I said, Gunn just completed a draft of Vol. 3, if they fire him they can't use any of his script without compensating him. Now, they could fire him and still use his script but simply compensate him for it, but that would send a bad message. No, a firing means completely scrapping any work he's already done on Vol. 3 and starting over again. Which isn't that hurtful to Disney since the movie is still in early pre-production, that means that like Roseanne having just finished her first full season, now was the perfect time to get rid of Gunn.
Add that all up and what does it tell you? It tells me they knew beforehand they could fire Gunn without triggering anything in his contract, they knew they could fire him without interrupting the production schedule of Vol. 3 and the MCU, they knew now was the perfect time to rid themselves of him and get a new script, and that they follow the pulse of Twitter quite closely to respond so quickly to an event that mainstream media sources hadn't even picked up on.
They knew all of this because they were waiting to get rid of Gunn and were prepared when the moment of opportunity arrived.