No. You shouldn't. If you hate the ruleset, then another very similar ruleset will not make you happy.
I would strongly suggest hitting your local Barnes & Noble to see if they're carrying a copy and peruse it. Then, if you like what you see, you can pick up the rules.
Actually, no. That isn't how it worked out at my table. I broke up monsters into logical groups, so there were more elements at play than Side A, Side B. It was NOT unusual to have the party split their actions so that they fell at the top of the round and the bottom of the round. The up...
I started using the "Popcorn" initiative method in a high level Pathfinder game (it would probably work just as well for DnD). All participants roll initiative to see who goes first. After that person has taken a turn, they pick the next person/participant to take a turn (and so on, and so...
I'd say it depends on your preference. In the games I've run, I've given the player a card with the NPC's statistics and let them manage the NPC. This puts the burden of determining the NPCs fate to the player; plus you as DM have a great opportunity to demonstrate to the players how serious...