It certainly isn't a bad design from ARC!
I used the VS110 to power Maggie 3.6R's and never had the middle transformer get that hot. Those Maggies were rated 4 ohms - with the tweeter drawing 3.3 ohms. The VS 110 drove them with ease.
Your SL3's are even more sensitive than my old Maggies - 89 compared to 86, so it's not a power handling issue. I wonder if there's an issue with the middle trans specifically? @lostbears has a point in terms of emailing ARC.
I used the VS110 to power Maggie 3.6R's and never had the middle transformer get that hot. Those Maggies were rated 4 ohms - with the tweeter drawing 3.3 ohms. The VS 110 drove them with ease.
Your SL3's are even more sensitive than my old Maggies - 89 compared to 86, so it's not a power handling issue. I wonder if there's an issue with the middle trans specifically? @lostbears has a point in terms of emailing ARC.