One word: balance.
I just LOVE the recon line, and the joy of suddenly whipping out my ASI high FF outta the blue and pwn everyone. However, strikers dominate lockdown. It is getting better now, but before there were just strikers, strikers, and MORE strikers. I do not hate them or love them, but I feel that the other classes should not be ignored. And then, DOWNTOWN and GARDEN comes along! *hooray*. Obviously, they have spikes and stuff. Perfect for the other classes, Guardian and Recon. When I used recon, it was fun and *gasp* actually balanced PVP. The strikers could kill you, but of course you could see them coming, not like BAM 5 skolver clones with GFs and FFs come outta nowhere: OHFU-*dies*. Alrighty, I know some of you hate downtown, and garden is actually okay for strikers. But it is a step towards more balanced teams.
Also, I like the scoring.
It gives you a chance to win if someone takes over all the bases for 60 seconds. You have a chance. More balance, I like that :P.
Final note: It was about time. And also, those maps are awesome. Bravo. I will play LD until another patch or a CE promo.
EDIT:
Thank you OOO, I love the maps :P
You know, a thank you doesn't hurt :,(