I think Agar could be a good choice for precisely the reason Batley Rhino mentions - that the squad isn't ready to mount a full-scale title challenge yet, and we need someone to oversee the transition from a position of stability. Agar will keep the current crop of players happy - this is clear for all to see - and he looks like a safe pair of hands to steer the ship while more contracted players are ushered out. The risk of bringing in a new coach while there are inherited weaknesses in the squad (a la Furner) is fairly high.
This is also about managing expectations. When we signed Harris in 1997, none of us expected to be winning silver ware immediately, but it signalled the team was going places and Bell did manage to steer us into 5th position after the disaster of 1996. This is a similar situation to where we are now. Agar needs to take Leeds into the play-offs, definitely the top-half of the table, and he needs to banish recent memories of flirting with relegation. Let's see how he does. We'll know in another year whether Agar will be suitable with (I hope) lots more dead wood coming off contract and some big signings for 2021. If not, GH and KS can make the call to bring in a more experienced top coach, and Agar can revert to his back room role.