The reality is that it will take intelligent use of ALL these materials to get it right.
So I thought I'd expand my thoughts. Note this is based on personal experience of falls, research and longish chats with materials knowledgeable folk.
Pretty much everybody agrees - The "bump" protection has to be held firmly close to the area it protects. And should NOT be able to move about. So either the item of clothing has to be stiffish, tailored and close fitting (such as bespoke racing leathers) or you need something like an Armour shirt - Some of which are seriously inspiring. There are a few marques - personally at the moment - I would put KNOX at the head of the crowd - simply because they are really thinking about it. 3-June-2018.
Then you need an abrasion protection. This is where the Para-Aramids and UHMWPE and even LEATHER come in.
Leather has a HUGE advantage aesthetically in that it is easily dyed. It is also (if used properly) quite stiff. This helps when something heavy (like a guzzi) lands on you and drags you down the road - it wont allow you to burst - first hand experience folks. This matters. Also this stiffness means it does not FLAP. Every time I put my Vanson suit on I am aware of reduced wind noise. Leather SHOULD be worn close fitting too. This has always been the advice. It will mould to it's user.
The Aramid family is heat/fire resistant so makes sense for example where potentially SUPER volatile race fuels are used. But cannot be used as an an external layer unless considered as disposable. And it does get damp and heavy when wet. It also as a liner is a very good thermal insulator (keeps you warm) - first hand - I know this. It is NOT particularly good as a flexible layer as it's properties as a material are quite the reverse of flexible. But used as semi flexible abrasion clamped between two layers of race grade leather - excellent. As a liner inside (for example hoodies) - I would not expect it to do much unless a GOOD SEPARATE armour layer is worn. Most fit so loosely that the armour inside is basically anecdotal. I wear mine over an Halvarssons Armour Jacket to stop that getting dirty. Also ime - Split upper/lower garments DO NOT offer full protection. I pce for track and zip together for road. That or serious overlapping (bib and braces with Jacket). In a slide if a garment abrades - it is catching on something - it will move rather than wear usually. Full 270° plus zips.
The UHMWPE I am looking forward to testing - as it is supposedly a thermal conductor (keeps you cooler) - It does seem to (shop tests) - but I need full sunshine tests to know. In theory (and practise) they can be external layer fabrics - but this means mixed warps and wefts - and so far this is ONLY available in DENIM which I dislike aesthetically. There is no reason why this layer cannot be bonded to a layer such as Goretex be it leather, UHMWPE or para-aramid. But that makes the layer less vented. My feeling is that UHMWPE and leather are going to be very very good indeed.
The Ethelene family of materials do have some inherent stretch, do not absorb water, will actually float (not that this is relevant to us) Are twice as resistant as aramids to abrasion, do not degrade in sunlight do not insulate (this also means they are NOT fire resistant). None of this is particularly new - but it's application to M/C's is newish.
Stitching matters - Now that we know Aramids degrade - UHMWPE - triple stitched.
Personally I would rather have a "disposible" waterproof outer layer rather than sacrifice venting in the abrading layer. Gets HOT here. Waterproof layers INSIDE are just (imo) silly. This allows the outer fabric to get wet/heavy and then chill as it wind dries.
This is perfect world.
But real world we want pockets (I get seriously miffed at the lack of decent pockets on bike gear - esp trousers) , venting (hot climates) - thermal liners (cold climates) - waterproofing. And mfrs need to offer off-the-shelf solutions to sell anything.
Layering is the key. The new family of materials just makes that layer-tailoring more variable. But simply believing that material "X" is the answer to everything is a serious mistake.
It is a brave new world - Long live the King - and his successors.