Debate can be positive but my experience is that it is not always so. There is the danger that people are pushed into corners, attempting to justify positions which are not built on rock (and don’t always need to be - logic is not always the sound base it’s cracked up to be, especially when it comes to matters of faith.)
In some areas debate is essential: political consensus, or agreements about concrete things like money, land, human rights and so on. People ranged on opposite sides fight then to achieve a workable compromise which takes both positions into account.
The same can be said of science. A debate concerning, for example, the Big Bang, or String theory can rage for decades, and needs to do so until sufficient proof is found to justify one position or another so that the search for truth (scientific truth I mean of course) can move on.
When it comes to faith, however, its an entirely different matter because we arent starting (or ending) with anything visible or straightforward. We each of us come to a debate about, say, the meaning of 'church' with preconceptions, tending to assume that the same preconceptions will exist in the people we think we are addressing. When we find that the preconceptions we had about the other person's preconceptions are plain wrong, we retreat into a position where we are attempting to explain our initial preconceptions as well as continuing with the debate that we started with.
The whole thing is doomed from the start and we become hot, sticky and frustrated in the process.
It's rather like me trying to explain the cycle of fifths to one of my pupils when they dont even know what I mean by a fifth, let alone a cycle of them. They may have a vague concept of what a fifth might be, and, of course, a cycle too, but you can guarantee that it won't be the same as my own until I explain it to them, and not necessarily even then . . . . and if you don’t know what on earth I’m going on about then I have proved my point.
The language of faith needs to be communicated amongst people who share similar experience of language: through community built up through mutual knowledge and understanding. Baptists, for example, share not only a building but a way of understanding the language of the gospel too, not just directly from biblical text, but through song and sermon, book and chat. The Catholic likewise: he grows up using language in a particular way, through nurture and communication. These (and of course all other) denominations are attempting the same thing: to approach God and to be as true as they can to the gospel message, and, although we have the bible in common, our use of language is still very different and the way that we interpret any given biblical text may also be very different. When a Catholic and a Baptist meet and try to discuss matters of faith it can be immensely difficult because of the nature of language and the way it is used differently in either place. As Eldad was saying, the room for misunderstanding is enormous and the great danger then is a retreat into hostility and rejection, which is of course the opposite of what we are aiming for.
That said, I completely agree that there is a great deal to be gained from engaging in cross-denominational discussion because it teaches us just how relative and how limited our own perspective and view-point might be, and just how much we depend on preconceptions, which, when challenged, can leave us with no room to move, and no air to breathe. It is a "way of the Cross" though because it can be painful and, superficially at least, even apparently destructive.
When I raised these matters in a contemplative Catholic forum recently I was accused of 'relativism' (which the Pope has been criticising so strongly of late) and my post was blocked. I personally reject the idea that matters of faith expressed through language can be anything other than relative. It isnt that the matter of faith is relative – it clearly isn’t - but only that the language used is relative. The Second Vatican Council makes this point repeatedly and this is still creating tidal waves through the Catholic branch of the Christian church which will take decades more to ease.
For me, the greatest danger facing the church today is fundamentalism: the tendency to either retreat into a corner when faced with contradiction and complexity or to come out with fists flying defending what we perceive as the truth, unable to listen and unable to change. The temptation to either is immensely strong.

After all, when we see God as He really is it will only be when all our own narrow and limited preconceptions have been finally swept away. Then there will be no language about God but only God Himself. In the meantime of course, the Word is essential, but so is Silence: guiding us gently but firmly towards perspective and depth.
Debate can be good yes, but, as Eldad wisely says, it has to be in a spirit of trust (seeking always the best in the other person) and kindness. We are few of us trained philosophers after all.