Canon 70-200 f/4 L IS with 1.4x or Canon 70-300 f/4-5.6 L IS or 300 f/4 L IS over Tamron 70-300 VC?

Thanks a lot guys.
Your inputs have been very useful so far. The amount of research everyone has put in for such a huge dilemma is very useful and it's really an eye opener.

This is what I have noted so far, please correct me if I am wrong.

Reasons to go the 70-300 L way:

1. Very good CA control all the way.
2. 300mm focus without external teleconverter.
3. L quality optics.

Reasons to go the 70-200 L way:

1. Almost same quality as 70-300 L if paired with TC
2. A tad better/ almost similar in the 100-200mm range than 70-300L
3. constant F/4 if no TC used
4. AF almost same as 70-300L without TC
5. Much lighter
6. Used version costs lesser than used 70-300L (from my research)

Reasons NOT to go 300mm F/4L:

1. Bigger, bulkier and less IQ than the other two 'L' lenses

So, overall, the 70-300 L sounds best from everyone's POV. The reason why I am hesitant to go the 70-300L way is because my Tamron isn't going to fetch me much if I sell it now and so, I plan to keep it for a while. The dilemma I face now is, getting a cheap 70-200 f/4 L IS without the TC seems good to enter the 'L' line up but then, if I do that I would use the Tamron more at the longest lengths but I would definitely be using the former for shorter ones and crop them because I know I will get a lot more detail with the 70-200 cropped than the Tamron at 300 without crop. If I get the 70-300 L, the Tamron is going to collect dust! I am slightly leaning towards having the 70-200 as a main lens and having my Tamron as a secondary lens just for the longest range. This might sound rude or stupid, I really don't know why but somehow the 70-300 L isn't as appealing as the 70-200 to me for some really weird reason that I don't understand. Maybe  I should rent it out and see how it performs just like I did with the 70-200.

So, for the last time, just to make a decision, let me ask this:

If you wanted the best quality in the 70-200mm range, which would you pick? 70-300 L or the 70-200 f/4 L IS?