I wouldn't take the term "crap" too seriously. Its going to be more:
1) mana efficient with reasonable conditions
2) mana efficient but moves slower.
Chris' definition that I quoted is a better metric to go by. "Crap" is always going to be format relative.
Look at me, being Mr. Literal over here, haha. I think I get what you're saying. Let me lay some examples... let's do them within the color white:
This stands in for all the removal that is conditional upon attacking, with the exception of
condemn, which is priced well below it's ability, mana-wise. What can this kind of removal in white do for your format? Well, it increases the power of red burn spells, for one thing, as these spells will rarely hit key utility creatures such as
merfolk looter that your opponent controls. I am personally a very big fan of this downside, as it balances the benefits and pitfalls of red vs. white removal in an interesting manner. Red can target-burn small creatures, but cannot stop large ones. White can destroy any creature, but not utility ones.
This will stand in as an example of all Aura removal, although
Pacifism would probably be a better universal example. I really like aura-based removal. Like
kill shot effects, many aura-based removal spells lack the ability to remove utility creatures (with the exception of some of the better ones like
faith's fetters, etc.) The efficacy of aura spells will depend on your format. A format with a lot of utility creatures/upkeep trigger trackers (dark confidant is an example of the second type) will see this removal as being less useful. Aura removal empowers utility creatures, just like
kill shot effects. I in particular like certain auras that have wider applications, such as
ghostly possession or
vampiric link.
These two cards will stand in as examples of all removal that is conditional on P/T within the color white. These kinds of effects can act as a slider for the power of aggro in your cube. The more 'puncturing lights' there are in the cube, the worse aggro, as early attacking creatures are easily eaten. The more Smites there are in the cube, the better aggro gets, as the general removal is less effective at stopping early aggression.
It is worth noting that cards like
puncturing light and
Terashi's Verdict in general are considered to be very low power. They also empower pump spells, as pumping a creature becomes a way to counter removal, on top of getting more damage in.
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These are just a few thoughts on some types of white removal that have glaring downsides. I'm typing this up in between shifts at work, so I'm sorry if my thoughts are a little disjointed. This makes me want to sit down and have a longer think about it, though, as well as doing this kind of thing for the rest of the color pie...