With the General's Handbook soon to be released I have put some points together on Matched Play an the associated army building rules. I won't go too much in to detail about the exact rules as most people have either seen the leaks or have access to a shop copy.
• Rules of one. These essentially serve as a limiter, they restrict the army builds that can capitalise on spell spamming, hit/wound/save buffs and infinite attack loop exploit.
• Behemoth cover. Monsters can no longer benefit from cover saves, which certainly helps against the more powerful Heroes (although most didn't fit in to cover anyway) but weakens the smaller behemoth models that don't have much protection anyway.
• Reinforcements. As part of your deployment you may now choose to hold back an amount of points during deployment to later reinforce your army. This is by any means such as, summoning or abilities which bring on extra units. Abilities which add models to a unit do not come under this rule.
Possibly the biggest shake up to the game so far, this drastically alters how you select your army. Having played around with this it seems to be fairly unrestricted unless you you want to stick to a certain faction and seems to generate some good armies which should be balanced for the most part.
• Leaders. There is a minimum of one per army and a maximum depending on size. These are the main units which can change the character of your army as you now have Command Traits, Battle Traits and multiple types of Artefacts for different Heroes. Some of which can really synergise with your army. Special characters however may not take any of these abilities but may use the faction spell lore if available, which seems fitting. Another important point to note is that you may take an additional Artefact for a hero for each Battalion Warscroll in your army list, this makes the cheaper Battalions quite viable just to get an extra Artefact.
• Battleline. You must have an amount of Battleline units in your army depending on the size of the game, certain units may be unlocked to become Battleline if your army list meets certain conditions. This will be the main choice for your army selection as it's essentially a decision between better Battleline units and unique faction abilities or wider variety of units and alliance abilities. And then another choice of taking minimum sized Battleline units to meet the criteria or instead building your army around them.
• Behemoth/Artillery. Both have a maximum depending on the size of the battle although this is not too restrictive for the most part.
Tournament wise this will eventually lead to mostly armies themed to one faction to get the better Battleline units and unique faction abilities. However the good thing is it doesn't limit anyone from taking a multi faction list if they desire and get their own abilities to use.
With tournaments the list submission will dictate how these rules play out. If you have to submit a whole 2000 point list then your units which may be summoned are restricted to what is in that list. What if someone wants to have a different amount of reinforcement points each game? Do they need to submit a list for each? It may even come to a point where list submission is no longer required.
Importantly with these rules, the units you bring on as reinforcements don't have to conform to your list building restrictions, so you may summon units from outside of your faction if able to do so, such as Nurgle Rotbringers summoning Plague Drones for example. Or you may summon another Behemoth even if your original list was at its maximum. This increases the options in list building quite substantially and is a good thing in my opinion.
One great thing for both casual and tournament Matched play is that people with a small amount of models can play someone with a larger force without having to limit the size of both armies. So if the tournament is 2000 points and you have only 1200 ready, you can still turn up and then summon your dead units back from your reinforcement points. This can be great for those who only wish to test the water with a small force or are very slow at painting!
These are my initial thoughts on Matched Play, I'm sure I'll have a lot more in the future especially on the list building side of things. I