If its only 1 halfling on 1700a there should be no problems.
Some more factors i just like to point out.
Fireball it down to keep it without econ and greed+storms on top of that MS.
Can spread your generals to bounce it down and eventually even conquest it down.
Make sure PF and well BG is active when you do. Emerald on top of that and use core attackers with other mods to increase the casualties for the halfling.
It can be a problem if they got 2-3 halflings like that and take a lot of extra time. But 1 halfling alone should not be all that hard if you explore all the alternatives you have to bring him down.
Sry if i post in this thread that belongs to you Flogger. I just wanted to pick out the obvious.
By all means MS+NM+Torn it also so it becomes in range before you able to break him.
Overpop works much better if they have tons of pessies but i would not want to leave a 1700a halfling on lots of pessies to make it even harder to bring it down. Id do both torns+FB.
Furthermore the base gain for conquest is decent in war and will put the damage where it belongs to take him down slowly but safely.
The only thing i see as a problem is if its a 1 vs 1 fight, but thats very unlikely and then the halfling will win. =P
Over and out