The buff also lasts a maximum of one minute now, so that means if you have the legendary cloak you cap out at 8 souls and any more than that is useless (since 60/(5+2.1) = 8.4 souls). I feel like that really reduces the usefulness of the cloak given that most of its benefit is either
a) in keeping the reap buff up while you're massively starved on souls because most adds on boss fights don't have any.
or b) being able to have the reap buff up for longer compared to a lock without the cloak.