Some very interesting posts.
With regards "advanced" cockpits I think there is a risk that some pilots could spend more time inside the cockpit than they should. There is a lot more going on compared with a "traditional" cockpit and a temptation to get caught up in button pushing. TCAS adds yet another component.
It is therefore vital that pilots become familiar with these cockpits as quickly as possible and remain wary not to let their skills degrade. There are some very good cockpit simulators around - as many hours as possible using these on the ground will pay dividends.
Never the less I recognise that there are those who will fly this type of aircraft and lack the currency on the equipment they need.
However, accepting this as a given, since these pilots "see and avoid" will have already been compromised, they are exactly the pilots that will benefit from TCAS or PCAS even more than those current and familiar with the kit.
There may be some confusion how PCAS and TCAS works. It is one piece of equipment that requires the minimal of "supervision" in the air.
In its simplest version PCAS only requires you to define the "safety bubble" on the ground in terms of horizontal and vertical separation. Once that done there is really nothing to do in the air. An aural alert will be given through your headset if another transponding aircraft enters the "bubble". Only then a quick glance at the display will tell you if the traffic is at the same height, above or below, its trend relative to you, its distance and direction in 90 degree sectors.
If see and avoid has failed it may just alert you to a serious risk. At two miles if you haven’t seen the traffic and it is at the same level as you it is well worth changing level - you still have time.