There are still some common events that are used as pumps, such as Wind That Sped Ships. But, event pumps are not very common in general.
Well, pumps at least bring with them a surprise factor. The problem with a weapon is that the opponent gets to see what it's going to be adding right away (though, in some cases, even seeing everything that's going to happen won't save the Free Peoples player --
Castamir and a
Raider Halberd comes to mind as a good example =P). While it's true that pumps aren't all that popular on the Shadow side, the times they do get used are because they're somehow better than the average pump.
Wind That Sped Ships, for example: +6 is a huge amount for one twilight, and part of why it works is because Corsairs are already large. This event allows them to get surprise overwhelms. If the limit were, say, +3 (or maybe even +4), you probably wouldn't see it nearly as often. You probably also wouldn't see it if Corsairs didn't have a few huge minions to begin with.
And look at
Savagery to Match Their Numbers, back in Fellowship: that was included in decks because it could basically guarantee 4 wounds (two wounds from the Uruk winning the first skirmish, two more for the fierce).
Whirling Strike is also great for surprise kills in Raider decks.
Yet pumps that just give a basic +2 (or +3 under a certain condition) aren't too common. Why?
Because, once again, the same theme seen in possessions reappears with events: you need something more than just getting bonus strength. You need something that warrants the card slot over a condition that will have a continuous/repeated effect or a minion.
The only culture I can think of off-hand that will use a fairly basic, not-too-huge pump is Dunland using
Burn Every Village. And the whole reason behind that is because playing against Dunland is a very "no-room-for-error" experience -- if you can keep them from controlling sites, you win. If they grab sites, there's a good chance you'll lose. Having that surprise pump in a Dunland deck is nice because so much of their victory chance can hinge on just winning a skirmish at the right time.