Changing the pull ratios, or the rarity of strong cards, would improve this. Changing the way cards are distributed at the prerelease - skewing probabilities so that chase cards are more likely than if you just bought the equivalent number of packs - would also improve this. But I have no idea how viable these ideas are from a business perspective, nor how it would address concerns from PTOs.
First off, "strong cards" are completely relative in the Pokemon TCG. Avoid playing into the hype.
But if you DO play into the hype, skewing card ratios for pre-releases is a bad idea. This idea reminds me of those "sampling packs" that we have now. Common and uncommon cards showcase what the set will contain. Reverse this concept and predict its consequences. Trainers and EX cards become rampant, making those once lucky pulls a bit less rewarding. Competitive players now actively seeking the more accessible cards they believe may be useful in the coming future. Ultra rare cards avaliable publically up to two weeks prior to official release, causing a flux in the secondary market. I'm sure there are plenty more. But if you're after the ultra rare cards, tins, booster drafts, and asking mom or dad already accomplish this quite successfully.
Personally, I don't think you can persuade players who buy boxes on the net by offering packs. Thus any notion of additional packs for a pre-release event is a moot point.
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If you want to add "prizes" to attract competitive players, or even financially frugal players, it has to be fair and avaliable for all participants. It has to be worth their money. It has to be exclusive, something special you can only get at the pre-release. It has to be useful, so that I want to get it because I can showcase it.
Pre-release sleeves was one of my reasons for attending pre-releases (shame no more Diamond & Pearl-like sleeves). All of a sudden, I didn't have to worry about protecting my rare cards because gracious TPCi has prepared me to play the game. I have a unique, useful item that I could only obtain by participating in the event. The deckbox was a nifty idea as well. But I need way more sleeves than I do deckboxes. I can replace sleeves easier than I can deckboxes. I can probably protect more cards using 60 sleeves than I can with 1 deckbox.
Provide exclusive pre-release promos. Now I think I recall reading a thread or post a long time ago explaining why this cannot be done. But if all participants received a promo only obtainable from being at a pre-release, it may encourage people to actually attend. Or make the promo more viable, like Dragons Exalted's Altaria with alternative artwork (although I would have preferred Gabite #89 or Garchomp #90 or Devolution Spray). Bring back the Winners promos, with one to each division? But with a catch: don't award them to winners of event rounds. Instead reward them to those players whose behavior at the event best reflects the Spirit of the Game, making them feel like a winner. Or provide sets of holo energy promos to attendants. I think I got something like that in my last player rewards.
And while you're at it, boost the Play! Point for pre-releases. Pre-releases are the only premier events where you get Play! Points, but you have to pay to attend. Encourage the attendance of pre-releases by providing a little player reward.
tl;dr. Any changes to pre-releases cannot be performance-based, but rather encourage a more fun, respectful, and enjoyable learning enviroment.