Just a quick question - are there any consequences to being a kleptomaniac hero? Or will at some point someone notice that I'm pretty much robbing everyone's home?

I loot almost everything and sell it, so I gain some prety amount of money, good for new equipement, if they don't see you, just loot all...

No police in the Witchers world.
I looted a giant 20-25 damage steel sword in the flotsam barracks. I'm only lvl 5.. This thing trumps any steel sword I'll be getting for a while.
It's random loot, so if you reload your save you'll always find new loot.
In that barracks so far i've found everything from "a big spoon" to halberds, hammers and shovels, all kinds of crazy stuff. Halberds and other long weapons are pretty good too, extremely long reach means nobody will have a chance to get close, and stun +15.

Geralt is no kleptomaniac. He is a poor, loathed witcher, whom people try to deceive in bargains and pay less money for more monster killing work. Plus, he is not stealing, he is removing useless junk from ghetto houses, which look like shitty warehouses at best! In real life, people are PAID to take away from your house useless junk you no longer have any need for, and random items, broken or in one piece.