By moving all the various terrorists groups in the west of Syria up into Idlib they turned isolated terrorists in their 100s or 1000s into a major army in its 10000s. OK I accept that putting them all in one place may make them easier to hit but that one place is hundreds of sq miles. Plus their human shield has been increased at the same time. They, like the SAA, have now had plenty of time to train, re-equip (looks at the uniforms now in most of the photos as a simple example), integrate their new arrivals, work out a strategy based on past SAA activity, establish defensive lines etc. We know they can be tough opponents when dug in and they certainly are now.
IMHO the Syrian Government is going to have to break their resolve somehow, perhaps with the RuAF totally flattening a key village/town with a couple of the largest possible bombs making the point that many of them will not die 'honourably' fighting facing the enemy, they will just die, crushed or vapourised. I don't know.
The upcoming Battle of Idlib will be one for the history books and will make the fight for Aleppo look like a playground fight.