I am not gonna bother with looking up examples of which one has more harsh words in this polarization issue. I also don't think it's really relevant, because they are all doing it and they all need to stop it.
I don't think Erdogan does it intentionally. Because there is no point in doing that. Matter of fact, it would turn against him (and it does), because he is at the leadership of the country. Having a divided country for a leader doesn't do him any favors. I think he is aware of this, and you could see this opinion come to fruition in his commercial (form last year or something), that went something like: 'beraber yuruduk biz yollarda'. But, the man doesn't filter himself when he is giving speeches etc. And I think this is Erdogan's both positive and negative trait. The people that love him, love him for this reason, and the people that hate it, hate him for this reason.
I also dont think half of Turkey hate and loath Erdogan at all. He was elected with more than 50%, and I base my opinion on the following survey:
Bu anket bomba! Erdoğan ezdi Davutoğlu sürpriz haberi
This survey is from december 2014, the most recent one I was able to find during a google search. And according to this survey, Erdogan enjoys the highest approval rating among all the leaders in Turkey. I personally don't hate him at all, but if I was also surveyed, I also would've answered negatively on his approval rating. His approval rating has dropped however, in 2013 his approval rating was in the 50% (survey was from after the protests).
In your post you said that the public approval rating was higher for AKP in their first and second term. And yea, Erdogan's rhetoric started to especially change in his 3rd term from what I remember as well. And it is disappointing to have witnessed that. I hope all the leaders will see their mistake and try to fix this polarization issue starting with themselves.
The coalition issue, the problem is, it doesn't end with AKP being able to form a government on itself. AKP won't be the first party for ever. And there will sure enough be a time where coalition governments can't be avoided after an election. And then, trouble will be in the horizon for the country. So, in order to safeguard the country's future in this regard, AKP's suggestion is the Presidential system. So far, Presidential system is the best solution I have heard for this problem. I am open to other suggestions, but haven't exactly heard any from the opposition party's. And from what I have seen from the oppostion party's so far, I am doubting their competence and not really hopefull that they will say something sensible on this issue. Hopefully I am wrong though, because my biggest wish for Turkish politics is for it's level to rise exponantially, to come to the same level (surpass even) the level of (for instance) Dutch politics.
And yes, Netherlands enjoys more civil, social rights etc. But despite this, one could still argue about the efficiency of the Parlamentary system in the country, is what I have been trying to say in my previous posts. Netherlands is doing well in my opinion, and that is due to it being a developed country, as opposed to Turkey, which is a developing country. Coalition's don't really hurt Netherlands, because the country is developed and it enjoys a high level of politics. But even despite this one could argue about it's efficiency. I feel like I am just repeating myself on this issue. Netherlands currently has it's own share of problem's too, like high jobless count, and budget cuts. But what country doens't have problems right?
I feel like I am just repeating myself over and over on these issue's and we have derailed this topic quite a bit. I'll try to not post a reaction, if you wish to react to this post. Unless I feel like I really need to.