That definitely sounds interesting, but of course it would require plarium to completely redo the castle upgrading system (and find away to compensate players who did upgrades under the old system). I'm sure there would be some upset players if you could wipe out 500k sapphires worth of building upgrades in a single attack :Pit was Lords Online by IGG games. they got rid of the browser based version and is mobile only, i quit playing then and never tried the mobile, but turn based PvP is there.
basically there is a big grid. your offense is on one side, and a castle wall is on the other. the defender moves first and sends units onto the grid to defend the wall, i.e. 300 calvary to the left side, 300 beastiary to defend the gate.
the offense gets to move say 300 paladins towards the center.
on defense turn they can move troops to counter act the incoming 300 paladins.
if the offense makes it to the wall they begin inflicting castle damage on each turn until the defender moves units to kill them.
You could essentially send enough attacks at a castle to knock all the buildings down to 0 and the defender would have to build all over again.
of course, build times are sped up and cost is greatly reduced.
but if makes you play defense rather than sit in the catacombs.