Before you go batstuff insane, saying "ROBOX IZ 4 LOZERZ AND 3 YR ODL OLOLLOL BOCKLEND IS T3H B3TT3R 1337 ELEET", read the loving OP.
ROBLOX pros:
Realtime physics
Lua scripting
ROBLOX cons:
The community
The fail-ass graphics engine that lags like hell
The fail-ass physics engine (when it lags like hell, which is usually)
The community
ROBUX and Tix totally ruin it
The community
Normal, Turbo and OMG Outrageoush!!!1 Builder's Club
Did I mention the community (of asspie five-year-olds)?
Blockland pros:
Fast, speedy graphics and gameplay
Event system
More user-created content than ROBLOX (script-, texture-, sound- and mesh-wise)
Lots of bricks with no lag.
Blockland cons:
No dynamic shadows for bricks via lights, only by the sun (and this doesn't even work for my computer... For some reason it only shows up when I'm a certain distance away, then fades, as I get farther.)
Vehicle physics, quite honestly, suck donkey dong.
If ROBLOX and Blockland were to come together, somehow, we would have a piece of epic on our hands.
Think of it, Blockland as it looks now but with physics on bricks, not when destroyed, but all the time (or when selected? $fxDTSbrick.Anchored or .CanMove or .PhysicsEnabled or something?). And we could attach wheels to the physics bricks and ride around in brick cars and stuff. And if you hit a wall, events in the bricks (or, take on the ROBLOX system and parent it to the bricks in a "group" sort of thing [doesn't Torque support that already?]) makes the bricks break apart. Maybe, the game could support Torque script and Lua script (Lua is fairly easy to implement) to manipulate bricks and stuff. This would, in my opinion, be one of the best games of my time.
P.S., I play ROBLOX AND Blockland, religiously.