Early in the game Lockpick is more useful in terms of frequency of finding upgrades. Just for balancing, later in the game you level more slowly, so great loot has to slow down, as well. Later in the game I started getting more equipment from random drops (regular or boss opponents) and merchants (particularly in Aleroth), but didn't get rid of Lockpick until I reskilled before heading to the Hall of Echoes.
I only put a couple points in Life Leech, and did notice a couple situations where it helped, but didn't check the numbers.
