Uh-huh...would I be a terrible spoilsport if I said that fast and good stall is a contradiction in terms? The whole point with being fast is that you don't need the stall aspect -.-
Anyways, ACC, I feel inclined to point out that you have too much fear monger in that second build. In fact, with the breakneck pace that true Magical Explosion wants to achieve, you shouldn't run that one at all because Fear Monger requires destruction by battle to pull off its effect while Magical Explosion doesn't really want your opponent to live long enough to pull that one off. The only reason I put Fear Monger in my own build is that the card library lacked the D-hero you really, REALLY want here:
Disc Commander
He's a draw two for flip's sake, what's not to like? Also, you'll want to have the standard recursion card that is Premature Burial in there to help Disc Commander pull off its draw trick. If you want to bump up the D-Hero count you could also consider one copy Dasher, since it can turn the otherwise nightmarish topdeck DMoC into a game-ender. The Warrior Returning is also a waste as it's completely clashing with Phoenix Blade. At the same time, I find myself staring in wonder as I try to figure out why you chose not to include Dimension Fusion, even though it's a central player in this type of deck. You can also quite happily drop Phoenix Blade to one since you don't really have that many warriors to fuel it with. In exchange for these, I'd suggest bringing in the optional killer combo of Magical Explosion that is Cyber Valley dupe.
So, like, to that build:
-3 A Feather of the Phoenix (With Valley you don't need these. Again, the only reason I ran them in my build was the craptastic card library)
-3 Destiny Hero - Fear monger
-1 Divine Sword - Phoenix Blade
-2 The Warrior Returning Alive
+3 Cyber Valley
+1 Destiny Hero - Dasher
+1 Destiny Hero - Disc Commander
+1 Dimension Fusion
+2 Machine Duplication
+1 Spell Economics (it's low utility, so only one copy; you should be able to thin your way to it 9 out of 10 games, though :3)
Personally, I'd also drop those copies of Spell Reproduction for +1 Mirror Force, +1 Torrential Tribute (or Threatening Roar/Waboku to replace those if you want some DaD protection). Even though the deck doesn't like it, you occassionally do have to give your opponent a turn and with the current pace of the format it's usually not a good idea to leave an open field for them to exploit. On the other hand, I'd probably cut a Lightning Vortex or two; with this build you'll want spell cards that you can drop to your graveyard as often as possible to quickly buff up Magical Explosion's burn damage. Card Destruction can also be run to speed up the dump and I have heard of some test variants running Plasma/Dogma to add extra draw power with Allure and Trade-in, but that's a matter of personal taste and I don't know how those look. =O
EDIT: Oh flip, can't believe I forgot. >.< Spell Striker is another common addition to Magical Explosion as it adds quick (and essentially free) fodder for Valley's 'draw two' effect.