I had a similar line of reasoning. There's no saving Hector's speed so it's best to have him handing that buff out to Linde and Ike/Ryoma.
it works surprisingly well. If anything I find it has the most 'uptime' of all my buffs in practical applications.
Hector moves so slowly he never separates from the group, so everyone's always in range of it. The exceptions are when Ike (and Ryoma in the future) tosses him around with Reposition, but even then I keep the sword guy close because they carry Fortify Res. Essential for Hector to take out super Reinhardts.
He's also either the first one to take damage (Reinhardt, Linde, Robin or archer), or he spends the fight doing very little until it's time to take out an Effie. Most of the time he's just chilling in the back buffing people.