Actually, after looking closer at Seyfarth I quite like him. The problem has been the Tigers play him out of position.
If he's given an edge for 80 mins he averages around 45 tackles, busy and accurate too with only 1.3 misses.
Sironen and
Curran in the same (2022) minutes are 10 tackles less with twice the misses. Albeit, they have an extra 20 run metres but they both average a considerable 10 pts less in Fantasy
He's listed as 1.94 cm and 103 kg so a lot of room to add muscle. At 24. could add 5-6 kg in a couple of years and become a handful.