I've installed hundreds of the Kichler LED pathway lights over the last 2-3 years. I've only had one fail, where I couldn't figure out why (the other two were hit by a bike or a car). In this case, the light just started flickering and eventually stopped working about 10 days after the install. Not sure why. Couldn't see any water intrusion or broken wires or anything apparent. I just returned it and got a new one. Easy over-the-counter swap. But that's the only issue I've ever had with one of them.
I've had more problems with the accent lights (spot lights) in the Design Pro LED series (e.g. the 15733, 15743, etc.). No issues with water getting in. The only issue I've had is the damn set screw breaking. And you cannot replace it when that happens. Just need to replace the entire fixture. Had a big lighting install last week with like 40 fixtures, and 2 of them broke right off the bat. We aren't ranking on them either. They just break sometimes. I hate that part of those fixtures.
As if this week, we're only using the new Radiax line. Those don't have a set screw in the back, line their previous line. We've installed a good 100 or so of the radiax accent/spot lights so far this year and haven't had one problem with them at all. I love the way they adjust compared to the crappy set screw on the old ones. Plus, I like the warmer color temperature (2700 K for the new ones vs. 3000 with the older ones) and I like the fact that they come with a cowl already too.
I am curious as to why you had two go bad like that. I haven't ever used that particular path light. We have always installed the 15810AZT, 15820AZT and the 15839TZT for all the installs we've ever done. And as I said before, never a problem with those, except the one time.