This is an excellent opportunity to clarify these issues, thank you.

Based on the rewarded (e.g. privileges) and exacting (e.g. duties) personal allegiance/loyalty/service between people

This sounds like you are talking about what /u/TheGreenReaper7 described here as:

...a certain type of property contract ('feudo-vassalic') where land is exchanged for military service, sealed by homage.

Is that right? It would be good to be clear from the beginning what, exactly, you mean by the term "feudalism". If that is right, then we can move onto the next bullet point:

That created a common social, economical and political landscape/background

Not really. As /u/TheGreenReaper7 said here:

In the context of a specific contractual-bond between two individuals (with military service being exchanged for land) then it did exist, but did not mean that the society was based around this contract.

Feudalism, in the narrow sense of this specific form of property contract, did not create a common social, economical and political background.

As /u/TheGreenReaper7 also wrote:

This would ... be [like] using rental agreements to explain how liberal democracy works.

Next bullet point:

A system, that we call with the word "feudalism"

I'm not sure that we could call it a "system". It's a form of property contract. It wasn't even the dominant form of property contract.

If, on the other hand, by "feudalism" you mean something other than this form of contract, then it's back to you to explain what you mean :)