I worked for Swissport at STN for just under 2 years on the FR side.
FR paid Swissport (then Groundstar) for 2 agents per flight to check in and 1 agent to board. The boarding agent was asssited by a cabin crew member who made the announcements and usually ripped the cards whilst the gate agent marked the cards off.
Whilst I was thurough at check in, the most I did at the gates was to check that the boarding card was for the flight I was actually boarding and maybe have a look at the passport/ID photo if the picture was being shown to me. It all came down to how good the cabin crew member was that you worked with. Some were great, knew what to do and did it quickly whilst those that insisted on checking every detail (name, picture, flight etc) HAD to be helped to prevent a delay on the flight. 20-25 min turnarounds were common and to be honest weren't difficult (for me anyway).
With regards to the comment made on Visas, it only adds seconds onto the passport check apart from the odd occasion when you would need to do a further check.
The team I worked in had between 60-80 PSA's on shift at any given time and there weren't many that you could work with who could close a fully booked flight on time. 189 people between two in 1 hour 20 was beyond most staff especially those that insisted on charging excess baggage.
I was constantly bollocked for not charging enough (it was monitored) but at least I could close a flight on time.
The major difference between FR and EZY @ STN is that EZY are computerised whereas FR are manual.
I preferred the manual way because it was just as fast as using a PC and when EZY had computer issues, their operation almost ground to a halt whilst we continued as normal. The only time manual checkin became an issue was during the peak periods when you had to call checkin for pax names. 1 phone, many flights and missing pax = delays.
Anyhow, I think I've strayed off topic there but I felt totally comfortable with the way I worked during the turnarounds.