The counters are presumably there to protect your guys from various attempts to remove them, and to prevent blockers from resolving. Negate is waay worse than mana leak, spell snare or remand, but it does half the job that those delver staples serve at the same mana cost. The usual gameplan of the deck is to play something like Young Pyromancer and back it up with spells, and negate helps that. Dissolve is probably too expensive, though I may be wrong. Chasm skulker is most certainly too slow for the deck. 4 mana give your guys unblockable conditionally is far too expensive, and this is not the kind of deck that plays land destruction. Also, not a huge fan of ogre battledriver, it's only good if you also resolve Young Peezy or Talrand, and it could be another spell to protect your threats.
Looking at the cards, I suppose you are referring to my deck so thanks for the input.
The idea I had in mind originally when building this deck was not only to be able to kill the opponent fast, but also have some cards that can help in the later game if for whatever reason the strategy falls short or fails to kill the opponent in time (kind of an aggro/control deck that swings more towards the aggro). That's mainly why I included the cards you mentioned and that are indeed quite slow for a pure aggro strategy. So that I can still have a chance to pull a win against most control decks even if they get their gameplan rolling. This has worked quite well so far, at least for me.
Dissolve is one of those cards, used to counter any big threat that may come in the mid-later game, while
Negate is obviously here only to protect your threats (mainly
Kiln Fiend) and also used to fuel Guttersnipe, Young Pyromancer and Talrand.
Regarding
Chasm Skulker, I admit he's mainly here because I didn't see much other choices of creatures to replace him, but it still serves as a big threat if the game takes longer than expected (the deck as quite a few draw cards for him to benefit from, and you have plenty of evasion effects to help him get through) and he's also a great removal magnet to protect your real threats.
Also for
Ogre Battledriver, I disagree that he only is useful for the token producing creatures. If for some reason your opponent has been good at removing your Kiln Fiends and other threats so far and you can't quite get one in play, the next time you draw one you want to be able to attack with it right away, you can't afford to wait another turn. That's actually my main reason for putting the card in, and the synergy with token producers is just a nice added bonus.
Tectonic Rift is indeed the card that is the most likely to go if I have to make a change. For some reason I felt I didn't have enough evasion with just
Artful Dodge so I wanted to add another card for this purpose, the land destruction just being an additional bonus. Yes it's conditional evasion, but it also applies to all your creatures which can be a pretty big deal if you have many tokens in play. So far I have always been happy to see this card in my hand and it has been very useful when I could cast it, but there were also many times where I couldn't/didn't need to use it. I'm not sure yet what I would swap against it though...