I've been using a Zealot for doing all kinds of L4 missions for the past two months(Bloods and Guristas). I must say that the Zealot is a very powerful ship but it takes a lot of thought in how you use it(definitely not like a BS).
I've been able to do all the L4 missions solo including the Extravaganza missions and the Kill the Informant. Having said this I should point out I trained all the laser specialization skills to level 4 plus the HAS skill to L4 and use Heavy Pulse II's and also try to tank as much as possible. I also use frig dogfighting tactics(get in close once the smaller ships are taken out and watch your six all the time and use an AB!), the key here is know the enemy and know their capabilities and the advantages and weaknesses of your ship(the EVE-I object explorer is excellent for this kind of info).
Of course all of this experience was gained at the price of losing 3 Zealots, oh well the fortunes of battle.
As for the pulse laser nerf, of course I oppose it but that won't stop me, and from the graphs posted it won't affect the close quarters portion of my tactics only taking out the smaller ships at a distance first.
Whatever you choose to do be prepared to lose that first Zealot! As I said it's a change from using BSes in missions(I used to use an Apoc) and experience comes at a price.
On the upside I've been able to solo a 5/10 drone complex to stage 7, it took around 4 hours but with the skills I learned in L4 DS missions it helped me immensely in complexes.
Sorry about the long post but I've heard the Zealot get some bad press mainly from people who want instant results and who aren't willing to put in the time and brainpower to figure out how to use it properly.