|Matthew is a rather underrated unit. He is one of the most versatile units that I have used. I had been running this same build with Rogue Dagger+, but he becomes an essential with the Sky Maiougi+ for all of those pesky knights that have been popping up lately.
For the most all-around Matthew, I would suggest a +Atk build (due to the drop in 4 points from + to neutral). I found that he becomes more effective in general battle with that added boost. That being said, a +Def would work just as well with this build, allowing him to tank more hits. With such moderate stats, I would suggest a -Hp or -Res so as not to take away from any of the other essential stats. -Hp is preferred if you want him to be used against dragons or mages as well. If strictly for physical battles, a -Res might be better.
Armored units have been taking over the game as of late. To counter this, Matthew with a Sky Maiougi+ is your solution. 41 Atk might not seem like much, but it can do a significant amount of damage against most armored units. With a +Def refine, Matthew gets a rather modest 33 defense, helping him to tank a few hits. It doesn't seem like much, but with his skill set his can effectively debuff every unit into glorified marshmallows, tossing sprinkles and rainbows at Matthew and the rest of your units. This is where Close Counter is ESSENTIAL. Without the ability to counter these physical units, Matthew essentially becomes a punching bag. Close Counter will let him 'roast' these marshmallows (bad joke, stay with me here...), with the added ignis obliterating any who oppose.
This same build, again, can be done with a Rogue Dagger+ for a more "general" Matthew use. However, if you don't ever want to have a problem with knights again, Matthew is your man.