Jack99
Adventurer
Plus, it's not like the two action points are going to be the difference in the BBEG winning or losing--if he uses them for offense, he'll lose by just a little bit less, ordinarily. But they can very easily make the difference between losing and living to fight another day, especially if the PCs have mostly used their APs.
Oh, and also, to respond to a question earlier that I don't recall seeing an answer to: solo monsters can, in fact, use both of their action points in one encounter. In general, no 4E monsters have limited-use powers that they might try to 'save for later', because in general there is no later for a monster--if it fights PCs, it's expected to die in that encounter. The 2nd AP for a solo is useless if it can't use the second one until after it's dead.
I thought you typically used a solo of 2-3 lvs higher than the party to ensure a climatic fight of sorts.
The idea is that if he goes nova in the 1st 2 rounds, he should be able to do enough damage to potentially take down at least 1 PC. After all, a PC is every bit as effective regardless of whether he is at full life or at 1hp, you ideally want to push him towards to ultimate status effect (death) ASAP. This way, with fewer PCs to face, this means fewer actions (which in turn translates to fewer attacks/damage/debuffs etc).
After all, I don't see what is wrong with the PCs killing the solo, then have him manage to cheat death somehow via DM fiat. They still get full xp for overcoming him regardless of which path I choose, so I see no reason to not let my players earn that.
While burst damage is indeed king, to use a WoW-ism, using it in round 1 is usually not the best solution for the solo. He should wait to be 100% to be able to get the healer(s). When they are gone, he can much better deal with the rest of the group. Killing people in round 1 will only result is them very likely being brought back quickly.