S!
So people complain now when they actually have to fly the Sissyfire? It was a plane like the rest of them, without a fly-by-wire

The trim tabs on ailerons, or any other control surface, were set to a certain speed where they kept the plane in a more or less trimmed state. Exceed this speed and it begins to roll/yaw/pitch and you need to counter it, either with trim if applicable or applying countering force with controls. This seems the case in 4.10m, which is good!
Same applies for Bf109 for example, it was trimmed with the aileron/rudder tabs to a certain speed, say 300km/h or cruise speed, where minimum input was needed. Many pilots state they needed to counter the changed trim especially as there were no pilot controlled rudder/aileron trims but only for elevator. In IL-2 you have always needed to fly the Bf109 due this, so if I need to fly a Sissyfire it is nothing different to me.
Just wait for SoW and we will need a brigade of Whambulances with the new FM if it is that complex as Oleg has stated. No more ridiculous planes on rails, which is good. US planes had the luxury of having all control surfaces trimmed and even boosted.
TD added some more pilot work and whining ensues. I wish all the planes would behave the same, requiring more pilot input so you can not just set the plane to fly and go eat lunch