Soft locks will show the target in the HUD which means you don’t have to rely purely on visually acquiring the target. TWS also provides an indication for speed and direction.
Also targets have to populate on the radar in order for them to be hard locked for R-27ER unless you are purely reliant on the HMD and only acquiring targets visually.
The only semi-effective radar mode that the Su-27 has is PD HDN and it’s still very slow to complete it’s scan pattern and give consistent update on radar contacts.
Being able to widen and narrow the search pattern is less functionality?
I can use wide scan mode to have 120 degree of situational awareness in the same time frame that it takes Su-27 to have half of that. Or I can use narrow scan mode to have much more frequent position updates from it and also reduce the number of subsequent enemy RWRs that I am pinging.
HMD does not assist in the detection of targets. You still have to visually acquire them. Having multiple ACM modes is helpful for acquiring close range targets that you know their general location but cannot see.
I.E tall scan mode is pretty good following a merge when maps are dark and enemy target is a small plane against a dark background.
Being able to tell the location and type of aircraft that is pinging you goes beyond just a defensive advantage. Also the Aim-9M is a pretty strong offensive advantage in Air SB.
It wasn’t even very dominant when it was Russia’s highest tiered aircraft in SB. It was still getting destroyed by F-16C without Aim-120, F-15A, Gripen, and Mirage 2000.
The only thing that has changed since then is the radar has gotten worse (double scan), the Gripen flight model has been nerfed (it still wins against everything but can’t just pull full stick back and do it automatically) and multi-pathing was reduced to 60m.