Led Ottawa forwards in TOI/G, 16G/27A/43PTS in 71GP, on pace for ~50 points in a normal 82 game season. Three solid seasons previously at 36, 28, 29 points.
Some possible comparables (looking for RFA forwards age 23-27 who signed 1-3 year deals:
Tyler Toffoli $4.6m. I think Brown is noticeably behind Toffoli, with Toffoli having had 49 and 58 point seasons, plus a injured 34 point season that paced for 44 points. Plus Toffoli had a 30G season under his belt.
Max Domi $3.15m. Domi had 52, 38, 45 point seasons, only 9 goals each in the two final years though. I would probably give Brown a small edge here based on better goal scoring and higher TOI / value to team.
Richard Panik $2.8m. Panik had a 22G/22A season prior to the deal, but his prior 4 NHL seasons didn't have production near this. Also well behind in TOI and relative team TOI. Strong edge to Brown.
Not trying to do a comprehensive list of comparables. My guess on Brown would be his arbitration floor is somewhere around $3.3m, ceiling of $4m.