You're probably better off asking on a more pro audio focused forum, it's not exactly ASR's bread and butter. And we'd need a lot more information to really give good recommendations. What's your budget? Use case? What kind of music/performance do you typically provide sound for? Are you limited on power, pack space, hands for lifting, etc?
That said, here's some general advice that applies regardless:
The KV2s you have are pretty damn respectable for their size. Since most top tier PA gear is passive (D&B, L'acoustics, Danley, Alcons), your options for upgrades are limited if you want to stay with active. Meyer is the obvious choice. A pair of X40s and a 900-LFC is about as good as it gets for a three box active system, but it's $$$. You'll need a processor for eq/gain/delay/etc if you don't want to do it all through your mixer. People also say good things about Adamson's active line, but I haven't personally heard them.
Why not passive? There are reasons passive systems are more popular in serious pro audio: fewer cable runs, easier to have backup amps in case of failure, lighter, cheaper to add additional boxes down the road. Most brands at or above the level of KV2 either provide presets for popular 3rd-party DSPs (eg Danley, Fulcrum) or their own proprietary black-box processing (L'Acoustics, D&B). If only home/studio audio would get on the bandwagon of smart amps and speakers that came with 3rd-party DSP settings...