You basically say that it's a pity that Christianity condemned mysticism because it was a way to God without the church in it, right?
Well, I don't know enough about such matters, I've once studied it in Church History, but I seem to recall that it was forbidden because it didn't agree with the things in the Bible. For instance, according to the Bible, people aren't meant to merge with the universe/god... We've been created to have a relationship with God and, if I've understood it correctly, in mysticism it isn't the case since you just... merge.
With all due respect, ChingChuan, I would question both your understanding of "mysticism" and Biblical exegesis.
Although many Christians may like to believe otherwise, aphorisms like "relationship with God" are modern rhetoricisms. These terms just aren't used in the New Testament and really weren't even used in Christendom itself until the last few centuries. I liken them to marketing slogans of the modern evanelical movement moreso than anything else.
Mysticism is explicit in the New Testament, most notably in the epistles of Paul and the Johannine gospel. The authors of these text make it very clear that the old "you" is epistemologically transcended (or, as Paul put it, "crucified") and subsumed within a deeper or higher Self (the Christ). This is mysticism pretty much as we see it throughout the world. Some exegetes have also seen Paul's injunction to "pray always" as a call for meditative awareness.
A lot of this is besides the point, though. The Church doesn't "reject" mysticism as a whole, given the high rank given to people like John of the Cross, Teresa of Avila, Thomas Aquinas, Dionysius, and Augustine. Even the posthumously criticized Johannes Eckhart was held in admiration by the late Pope John Paul.
The trick to Christianity and mysticism is you can't be too blunt when you're talking about it. You have to "hide" your experiences and explanations in appropriately churchy rhetoric. Of course, that isn't good enough for some of the hard-liners out there. I once heard a modern Christian complain that St. John of the Cross was too "Buddhist" for him.
Go figure.
However, fortunately the way to God isn't controlled by the church (anymore) and it has never been since Jesus is the only way to God (according to Christianity, that is).
According to the Gospel of John, you mean. Such claims are not found anywhere else in the New Testament, certaily not in the other gospels.
Curiously enough, it is only in the Johannine gospel that we find these "I Am" speeches and it is only in this gospel that Jesus is identified with the pre-existent Logos (a familiar concept in Greek metaphysics). It is highly evident that the "I Am" the Johannine author is talking about is the Logos. Jesus is merely a symbol or manifestation of the Logos.