Her blog was popular. I read it too. Not because I agreed with her. Go read the blog, yourself to see what kind of person she was.
Most people hated her because she was mean and her pastime, when not professionally attacking politicians on the other side of the aisle, was to dig up dirt on their spouses and acquaintances and attacking them on a personal level. [5]
For example of the kind of shit that she would engage in: Here she is reposting revenge porn. The victim is an acquaintance of some random major of some random town that leans towards the other political party. The major did nothing wrong nor was she politically relevant in anyway. This was her bread and butter "journalism". [1]
With regards to the car bomb, I'm not sure what you are saying here. I am not denying that she was murdered using a car bomb. Are you saying that this implies a high level actor? Far from it. Low level thugs and organized crime members kill each other with car bomb frequently. [2] [3] [4]
One last thing. With regards to the whole Panama thing, that was potentially her only work that could be see as real journalism. But also that situation is being misrepresented. The entire picture is more complicated. The thing is that she was part of a faction of the opposition who had previously been in power for 25 years and where themselves corrupt. So much so that despite the whole Panama scandal thing, the recent election saw the newly in power PL government widen the gap by a very huge margin of 40000 votes out of a few hundred thousand. Basically the statement by the electorate was, "we do not care that the PL are corrupt, you guys were equally corrupt and for much longer, at least the PL as improving things elsewhere". This resulted in the her party basically disintegrating and is currently fragmented and disorganized. This is why I said that a political motive does not make sense. Because there is no reason for it. The electorate wants the PL to lead the country for a few more years despite the corruption because they are so fed up with the PN.
[1] NSFW Link: https://daphnecaruanagalizia.com/2015/09/bottom-of-the-barre...
[2] https://www.timesofmalta.com/articles/view/20160116/local/ma...
[3] https://www.timesofmalta.com/articles/view/20121003/local/Po...
[4] https://www.timesofmalta.com/articles/view/20130607/world/bo...
[5] There were reports of people celebrating her death at the university and elsewhere. That's how much they hated her.