I learned something new today; An aspect must be tagged as soon as you can - you can't put off tagging it to do something else (such as generating more aspects). The vampires can't wait to amass aspects cause they need to tag them when they perform the action.
Not true. "A tag is subject to one key limitation: it must occur almost immediately after the aspect has been brought into play. Some minor delay is acceptable, but should be avoided when possible. At worst, a tag should happen sometime during the scene in which it was established." (YS115)
The ritualist on the other hand, can generate and tag aspects, generate and tag - because declarations are part of the preparation for the ritual and can be tagged in advance, they don't have to be tagged while casting the ritual.
Not precisely true. For rituals, you are not making Declarations in the same sense of the word as used elsewhere. Instead, you are "declaring a mini-scene (represented mechanically by a skill use) relevant to your preparation". The difference is that mini-scenes require a (TBD) time commitment, whereas the standard Declarations don't. In this sense, ritual-flavored mini-scene declarations are more akin to Assessments than Declarations.
Secondly, applying aspects on a target (i.e. the Ward) allow the target to defend as approriate. You can't just declare that your target has that aspect by rolling a 3 or higher - you need to roll higher than their defense.
If the target is an opponent, then they get a defense roll. If the target is the environment, then the difficulty is fixed and is determined by the GM. This is for maneuvers; declarations use a different difficulty system based on how interesting the declaration is. The difficulty of '3' only applies as a minimum power for spell-based maneuvers against the environment.
Third, when attacking the Ward itself, the ward's strength is a stress track but that only applies for attacks exceeding the ward's strength in the first place.
So it seems. Which means that the leeches would have to go with the 'dogpile' strategy, applying maneuvers until they had enough taggable aspects to knock it down (or at least to damage it, thus avoiding damage themselves).
Perhaps when in doubt, put a max limit equal to lore for aspects you can tag for a ritual... requiring the rest to be invoked.
I'm kind of thinking that using Lore as a limit on the number of mini-scenes that can be declared to power a ritual might be pretty decent as a guideline. This would create a soft "limit" of triple your Lore for a ritual's complexity. Of course, you could still invoke other aspects with Fate as you mentioned, or take consequences, etc to build it up higher. Another way to provide a limit might be to increase the skill roll difficulty for the next mini-scene based on the number of mini-scenes already declared. (Ie, still limited based on skill, but less directly.) Note that I'd include "scenes skipped" in this total.
I understand why they wanted to keep the rules a bit less than fully defined, but at the same time, it seems to me a ritual "story" should rely on a handful of flavorful, pithy mini-scenes, rather than a long checklist of standard preparations that are undergone procedurally for every ritual. Otherwise, why wouldn't *every* Wizard have a 60+ strength ward with a duration of their expected lifetime (about +12 on the time chart, assuming a duration of "several mortal lifetimes")? Even if the Wizard just prepared by resting a lot (using the basic +1 per scene), this would only take a few days (or a bit longer if he threw in a few more bells and whistles), and then he'd never have to worry about it again. (Not even if someone breached it, since anyone breaching it would certainly shorten the Wizard's lifespan to "a few moments" if not "instant".)