I really like Frenzy, personally. I dunno if it's exactly how it works in normal D2, but I did a lot with it in Nez. You know how it has a range of increased speed and attack speed and stuff in the details for what the skill does? The first hit you make with it pops up to give you the lowest bonus it describes, then each successive hit while still under the effect of the earlier bonuses will add it up and stack it until you reach the max bonus for the skill's level.
As in, say it says it enhances your run/walk speed by 10-20%...first hit gives you 10% faster runspeed, and more hits builds you up until you cap out at 20%. Increasing the skill level increases your bonus ranges.
In Nez there was a socketed belt that gave any character Frenzy. Of course, only those who can equip two melee weapons can use Frenzy, but it allowed me to make a Frenzy claw Sin that freaking raped. Frenzy can be really good if it suits your play style and you enjoy the way it works. Personally, it's my barb skill of choice.