Can you do it - yes. But I would not recommend it, and it will not replace +heal.
If you max out int, and have barely any +heal, then you will be an inefficient healer for a longer period of time (and maybe you won't get that life-saving heal done in time). OK for general purposes, but not good in emergency situations.
I would not count on crits since they are chance. +Heal will always help, and is consitent. Thus, +Heal will be more reliable and effective. +Heal gear generally comes with +int, so you get the benefit of both (even though it is a bit less than +int gear).
Per my previous post - do the math to figure out if it is better than the MP5 value on pieces you find. However, it is all preference as to what you are trying to accomplish. You can think "ouside the box" all you want, but different situations have different requirements. You can't have the one magic setup that fits all applications.
If you prefer to dish out smaller heals, then go for the +int. As with everything, you need to find a balance. We can not tell you what will work best for you.
EDIT - I would be interested to hear your results if you do try it though. :)
Edited, Dec 14th 2007 4:45pm by YJMark