It locking you out of summoning is good and all but nothing is stopping you from summoning them beforehand as youkais themselves add to DPS overall or just use summoning storm and summon 6 even while under the effect (Yes, that works). So you can just walk up to one of the many you summoned, use the ability, now you have 80 SCALED strength regardless of race.
As I've mentioned before, this is one of those items, if you buff too much will instantly become a meta pick with pending nerf threads. This is why I'd rather the trade of lowering the scaling for longer duration than increasing the duration by so much while still keeping the 80. Because at that point, nothing is stopping you from making a doom tank and gain that much top tier strength for that long.
As I've mentioned before, this is one of those items, if you buff too much will instantly become a meta pick with pending nerf threads. This is why I'd rather the trade of lowering the scaling for longer duration than increasing the duration by so much while still keeping the 80. Because at that point, nothing is stopping you from making a doom tank and gain that much top tier strength for that long.