I think you're right to point out that there is no real doctrinal Judaeo-Christian vs Islamic divide.

But I do think you've fallen into the trap of assuming another divide that doesn't exist.  You've picked out bits of evidence to support your argument, but it's much more complex and the links and differences between the faiths much more evenly spread.

Dietary laws have something to do with religion and must be observed? Check.

As has been said, that's something that has fallen out of the Christian calendar only relatively recently.

Males must be circumcised? Check.

Circumcision is not, according to Yahiya Emerick, a religious sacrament in Islam, but a custom based on a desire for hygiene. Some American Christians are circumcised for the same reason.

Christ was not divine? Check.

True, but you could just as well make a link between Judaism and Christianity on the basis that neither recognises Mohammed.  Or between Islam and Christianity on the basis that both recognise Christ.

No concept of the Trinity? Check.

As above, because if Christ isn't divine, you don't need a Trinity to fudge the issue of there being one God with a son who is also divine.

The idea of "Love thy neighbor as thyself" plays no special role? Check.

Charity is one of the five pillars of Islam. (And one of the most important mitzvahs in the Torah). To me that seems to be one of the things all three faiths have in common.

Judging from this, it appears that Islam is nothing more than an adaptation of Judaism for non-Jews. Whereas Christianity was a reformation of Judaism.

Jesus is revered as a significant prophet in Islam, and will return to life as God's agent at the Day of Judgment.

It could therefore be argued that Islam is a reformation of Christianity...

None of which, of course, invalidates your question...