I've got two, one permanently in a router table and one for freehand work. They're very good machines, I regularly copy rout curved legs in 50mm hardwoods and plunge through mortices in oak without problems, but equally they can cut 1mm inlay grooves with absolute precision. The only reason you might think you want even more power is if you were chomping through kitchen worktops all day long. In any event, I wouldn't want to ever hand hold with a bit that the OF1400 couldn't handle!
If I have a criticism it would be visibility when fully plunged and bit access with some of the extraction hoods fitted. Also even though the dust extraction is exceptional, the OF2200 is just that bit better...as well as being more "user friendly" in areas like Festool track compatibility. I don't own an OF2200 by the way, but I've used a few, and once you get used to the humungous weight they're pretty impressive.
The comparison with the OF2200 is an interesting point, the OF1400 is actually getting a bit long in the tooth, it's already had a couple of upgrades and the OF2200 introduced a number of benefits which could be adopted by the OF1400 (extraction and improved interchangeable bases are two off the top of my head). I've no inside track on Festool's intentions, but I wouldn't be surprised to see them replace the OF1400 with an upgraded medium sized router before too long. But hey, if the current model meets your needs then why wait? I doubt I'll be rushing out to trade in my OF1400's if and when a new one comes along.