You implicitly touch on it, but another major factor is just the severe limitation of one's options due to the requirement to only date JWs. In my view, JW women are often forced into a very limited role - they are not allowed to develop interests or ambitions, not even to the already reduced extent that JW men are, because they can't progress in the organization beyond spending a lot of time recruiting. This is all well and good for the type of misogynistic, controlling and overbearing men that want a submissive wife that will simply obey him (this is also the type of man that does extraordinarily well in the org, it seems) but for men who truly want a partner and someone who thinks for themselves, it leaves few options. I'm sure women in the cult face similar difficulties finding a husband, probably in the opposite direction - I imagine it's difficult to find a JW man that really wants to treat his wife as an equal.
The dating requirements that ensure, if followed, that you will not be able to adequately evaluate compatibility prior to marriage (requirements of a chaperon and that sex is off the table during the dating are not healthy ways to find a marriage mate, in my view) further compound the problem that is caused by starting with the "on paper" requirements for a spouse that you described.
Then of course hormones tend to cause JWs to marry young when the rules are followed (or coerced to marry young when the rules are broken). Even if a JW can fight the hormones and not get in trouble, the fact that the culture is to be married before 25 results in a sense of urgency to find someone. You don't want to find yourself at 30 with your only dating prospects being 18 year old girls (creepy) or divorced women with kids (nothing against single mothers, but when you're 20 and looking at the future that seems like a prospect that should be avoided).
All this adds up to people marrying too young (before the brain is fully matured at around 25, the personality can continue to change drastically) and getting married to people they're often not compatible with. And this is all before one of them wakes up to TTATT.
My wife and I definitely had our share of common interests, as I was luckily smart enough not to restrict myself to someone that was super zealous and really look for some common ground. Of course that only goes so far, and we certainly have some pretty big incompatibilities. But upon waking up I'm finding that there's two major difficulties to the marriage that don't have to do with incompatibility that was apparent while I was a JW. For one thing, after waking up as a born-in, there is a normal (at least I hope it's normal) desire to reclaim your lost adolescence and really explore the world and life outside the bounds of the cult. They kept me so repressed for so long with so many rules and now that the arbitrary rules are gone, I want to explore and find my own rules and limits. If only one spouse is awake, this is a process that the still-in spouse is likely to be threatened by and resent. And, speaking for myself, its difficult not to be displeased with my wife's efforts to slow this process of discovery and growth.
Another issue that I have in my marriage due to waking up is my disgust at the cult that my wife remains involved in. It feels to me almost like I was raped by one of my wife's friends or family and upon telling her of this she only digs in and pursues a deeper connection with my attacker. It's difficult to get past her affiliation with the cult after I've given her every chance to wake up and see it for what it is. She values it more than me, and that's not supposed to happen in a marriage (to be fair I may be coming to the conclusion that I value my escape from the cult more than I do her). My wife is certainly loving and has made some effort...but I don't think she will ever leave and I'm not sure that anything short of that will be enough.
