more data
Not the official word, but interesting, read what our TO for prerelease told us:
San Diego Pre-Release Constructed Format
Basically, Expedition onwards with promos dating from its release (Sep 2002); if you read the thread, you'll see the detail on which promos fall in that category.
I have to agree with those who are stating that the play environment in the near future would be far less interesting if the (Exped., Aquap., Sky) E-cards were rolled out of modified.
TTar666 has completely covered the supply question. Obviously, its the general case, but it is a very prevalent case that you can still get a lot of Expedition & Aquapolis & even Skyridge in retail outlets, small shops and certainly online.
It would be decidedly against the 'compatibility' advertised for the R/S EX series to say that it was only in unlimited you could play the old cards. The energy removal in unlimited makes 95% of Evos unplayable. It would be UNFRIENDLY of Nintendo to make us put down cards from the e-Series at this time; I don't expect it. Those who do are, in effect, stamping a company that wants as many players as possible to stay in the game with an attitude more conducive to a company that has other games they want people take up.
LC? Well, I played some cards from it with success. Oracle/Bill is off the charts for composing successful Rogue decks (search two to top of deck, then draw two off top of deck -- bingo!). Trader & Breeder. Some Pokemon (Zapdos, Venusaur) were elements of winning decks. If you don't know these cards and want to understand them, check them out at Pokeschool, Pokemon Zeo or Pojo (try google). So, LC will be missed, but it doesn't cut the legs out from the environment. Anyway, I think we'll see some of those cards again someday, maybe sooner than later.
So, e-Card On, or EON, is 'good times' together with EX and the latter promos. I consider the last modified to be the richest play environment since I entered the game (fossil), EON, even without Dragon, looks like fun. Dragon won't be the last release where e-card sets are legal in modified either, I don't think.