We're considering several comp. restrictions here for tournaments.  Unlike 7th, the basic Eighth Edition has some issues at the moment.   Seventh had problems, but they were in the army books.  I would love to get some feedback from outside our local forums on this, so please go nuts in the comments section.  Here are some basic ideas, cribbed liberally from Australia:
1.  Remove the Power Scroll
2.  No Special Characters
3.  No single items that are greater than or equal to 100 points. 
And then the ones with options:
1. MAGIC SPELLS
This seems to be generating the most discussion in  other threads post Pilgrimage so I'll start here. It was also the single  largest issue in the unbalancing of games. In the last edition, the  restrictions/comp systems developed were an effort to balance armies out  so that the best general, and not the extreme powered army, should win  most games. What I saw on the weekend was that in about 10 out of 43  games EVERY round there were devastating big spells that removed  generalship from the equation and annihilated characters and units from  the table. the were games where the first one to roll a double 6 would  win. of those 10, 5 would be over in the first few turns from such  spells. In others, the superior general of a game would be on top,  winning by a big margin, and all the opponent needed to do was roll a  double six on a purple sun/ dwellers below, etc and characters and units  would disappear and the game reversed to a big win to the lucky but  poorer general of that match. We've all heard stories of this happening  every now and then in the last edition, but in 8th its a regular  occurrence. I think it will be too problematic to re-write some of these  power spells so instead, in the name of balancing the game, they should  be omitted. However, you might have a different idea, so below are your  vote options.
A. Do NOT allow the most powerful spell from each  deck/15+ spells
B. Modify these spells to tone them down but so they  can still be used
C. Use these spells as they currently are
2.  MAGIC POWER DICE
The GW FAQ ruled that the 12 power dice limit was  the amount of dice that could be in the pool at any one time, but there  was no limit on the number of dice that could be rolled in a magic phase  of dice continued to be generated, such as from dark elf  daggers/spells, death lore casualties, Slann extra dice, etc. At The  Pilgrimage we set a 12 dice allowed to be rolled limit in both power and  dispell dice and am glad we did, even without the power spells more  than 12 dice would unbalance the game.
A. Use a 12 dice rolled limit  per phase
B. Have no limit on the dice rolled per phase as per rule  book
3. WAR MACHINES
War machines are a lot more effective  than they used to be, they no longer require range guessing skill to use  and there are no partials but some are much worse than others. 3-4  elven bolt throwers are no where as effective as 3-4 tooled up  Empire/Dwarf war machines. We used a 5 war machine cap at The Pilgrimage  with the steam Tank counting as one. Because of their effectiveness I  believe they need to be pulled back a tad more, I would suggest 4 War  machine models max.
A. Cap Warmachines to 4 max
B. Cap Warmachines  to 5 max
C. Do not cap Warmachines
4. SCENARIOS
There are 6  Pitched Battles now, at The Pilgrimage we used Battle Line, Battle for  the Pass and Meeting Engagement, twice each. This favoured armies with  shooting and magic as in 2 of these scenarios you can have a very deep  deployment where a combat army will have to trudge across a lot of table  while getting shot at. If we had used all 6 scenarios these shooty  armies would not have been able to compete in scenarios like Blood and  Glory where the deployment is very compact and forces you to have many  standards or The Watch Tower where you need to take a building to win  the game. Using the 6 scenarios would have forced a more balanced army  build.
A. Play All scenarios
B. Play selected scenarios (list  which ones)
C. Play only Battleline
5. TRUE LINE OF  SIGHT/TERRAIN
There was a lot of discussion on this pre-event, but  during the event it seemed to have very little impact. There might be a  story here or there of how a monster could not hide from a cannon and so  on, but overall, people seemed happy with the way it works. The very  few comments I heard from players related to their concern for abuse,  where some people might have non GW models that get an advantage by  being smaller. We could easily get around this by saying that all models  are considered to be of the equivalent GW size and if there are any  doubts the situation goes against the person not using the non GW size  model.
A. Use TLOS as per rule book
B. Set heights for terrain  (such as hills being infinitely high)
C. Set heights for models (such  as models hiding equal or smaller size base models behind them)
D.  Use both B & C