@ Marton:
I completely understand that Mana Draining a Force of Will nets you 5 colorless mana PLUS the mana you have untapped next turn(edit: Next phase which can make it better or worst depending on the game situation)
I know that is a whole lot. I´m not saying Mana Drain is bad at all, however it IS conditional to your opponent casting expensive spells, because you simply dont want to waste a drain on something where you just cant reach the amount of mana you needed to cast what you wanted to cast.
Say I have an island and a mox sapphire and I want to cast gifts ungiven with my drain mana and my opponent casts a recall. I don't want to waste my drain for something that doesnt allow me to cast the gifts, but then again i cant let him draw 3 cards either. So I have to counter his 1 mana spell and hope for a land.
Well, in that case mana drain is 'sub-par', but you must keep in mind that there's hardly another card that is going to get the job better done than mana drain. Misdirection would, but that card has high probability of being useless in a good number of matchup. Even then, it is less likely that you have an extra blue card in your hand than the likelyness you have UU open. I would say that the best way to interpret that scenario is that mana drain would be optimal if it would counter a 2cc+ spell. But in this case it's still very good to have the ability to deny the opponent from drawing 3 cards. Plus, you might draw into a mana source on the next turn, so that 1 mana could allow you to cast your gifts ungiven. This is also why mana drain is soo good; since you don't want your opponent to abuse it, your own spells will tend to be in the 2-3cc range, with some 4cc. If you analyse the curve you quickly realize that it becomes very easy to make use of the mana that mana drain grants you, 'whatever the amount'. Now take that into consideration, and compare it to this:
[...]however it IS conditional to your opponent casting expensive spells,
. I have explained why I do not agree with that statement.
Goblin Welder needs artifacts in the graveyard to perform
Correct. But even just having one black lotus can turn welder into something really broken. The 'setup' required to make goblin welder is very minimal, and it IS a 1cc threat. What you need to keep in mind is that it is 'conditional', but the cost of the card itself is so low, that even if it is conditional, it is still worth running. It can be used to return the artifacts you got countered, and can be used to mess with the opponent cards (ie: welder/shaman to destroy null rods, etc). The number of cases where this card is dead is rather minimal to really consider the card much conditional.
Coretapper needs artifacts that use charge counters to perform
That is exactly why coretapper isn't much played. It is better to counter the artifact than the coretapper. Which means in fact that we don't really care as much about the coretapper, since it is hardly a threat by itself.
The point is, if you're not conditioning your deck, you will be outperformed by your opponent, or rather out teched.
You have yet to prove that point.
What you are saying is that Will is insane (which is true) and Goblin Welder is as good as unconditional(which is true), but the reason WHY will is insane and welder is unconditional is because the decks that use them make them become insane each time you draw one, the cards are carefully evaluated and picked to assist the gameplan. You can dislike coretapper all you want, he was just used to set an example; but the truth remains that when you design your decklist to follow a certain plan, it can make otherwise crapcards that do nothing on their own, aid more than half your deck. A good example on this is Krosan Reclamation that Randy Bhueler used in Meandeck Gifts/Oath.
I fully agree that otherwise crap cards can turn into good cards when the interaction is found. Recoup has long been ignored, until gifts started getting more play. I even believe it was used with intuition at the beginning, but anyway, it's not relevant to the conversation. Tormod's crypt was long crap, until the metagames changed / new cards appeared. However, the interaction must be really strong to make the card playable. Which brings me to the next point.
If you take a look backwards at the evolution of decks, you will notice that almost all of them evoluate in a way that they abuse and revolve around the most powerful cards around, the rest being just more-or-less fillers. Yawgmoth's will, being invariably the most powerfull spell, is the card that all decks try to abuse as much as possible. If you take a look at the last 2 years of deck evolution, it has been a race towards decks that abuses the most yawgmoth's will. One example would be the suicide-virus deck, by mike long (I believe). The sole purpose of the deck is to play yawgmoth's will. Even the 'article'/email that unleashed the deck very much squarely said that the best decks should be built around the best cards. While the suicide-virus decklist is arguably crap, it is still designed by someone who (should) know what hes talking about. This leads me to my point: the 'crap' cards cropping up tends to be played only because they revolve around the best cards on your deck. The only way you can play a conditional card is because it has a strong interaction with the best cards of your deck. Recoup (and arguably burning wish) are very-much-so exactly that. Conditional cards are played when the delta (difference) is high between the lost tempo of when you cant use them (due to their conditiality) and the tempo gained from when they are actually good (condition met). In other words, the benefits must justify their conditionality. The only way you get a benefit worth mentioning is when your 'crap' card interacts with your best cards. The only other case I can think of to use a conditional card would be one that is gives you a lot of tempo, but is very narrow (ie: rack and ruin). But that is a different discussion since narrow cards and conditional cards arent the same thing.
About freespells, look at Land Grant next to GrimLong or other Tendril versions. I think alternate CC spells are underplayed right now which is a shame cause, specifically crash, is a crazy good card.
You don't play freespells in a deck because you can. You play the cards that best matches your game plan and that improves the most your worst matchups. Alternatively, if you make a hate deck (which by definition is crap, and rarely wins big tournaments), then you will ignore your bad matchups and keep playing more cards towards hating decks x and z. In both cases, it is not indicative towards just 'playing free spells'. Play the cards that gives you the most tempo, not the ones that costs you the less tempo.