Hoki said:
I don't think there are limits to how much a spell can be modified. Remember that Subaru, a new Belkan style user, has a Divine Buster. Her buster is different because it is a close combat spell, but it essentially follows the concept of Nanoha's version. Erio has a thunder rage variant. Teana learned Starlight Breaker, and now has her own version.
Just an fyi, but the limit is actually more inline with what the caster is capable of, and what they want to spend the mana on. In other words, what is easiest/best as determined by the caster themselves. If Subaru had the mana reserves, she could very well fire a Divine Buster like Nanoha. In reality, she only named her spell Divine Buster, because it was a fangirl thing. But overall, a mage determines what variables they want their spell to have, and that is constrained by what they are capable of, and what they want to achive.
Divine Buster is a fairly bad (or interesting) example to use, since it is designed more as a variable spell. It is the spell that Nanoha uses when she pumps variable amounts of mana into it. In contrast, Excelion Buster has two main modes: a single beam that is generally stronger than DB, and a multi-beam more called "Force Burst." So she if the situation doesn't call for either EB mode, or she needs something a bit more complex, she uses DB.
In simple math terms, EB would be like quickly recalling that 5+3=8, or 4+4=8, whichever you want to use. Divine Buster is more of x+3y = z, which allows for more leeway due to variables, but also more casting time (except in the case of the short DB version she developed, which is faster and can be fired on the go, but is less powerful).
Bottom line: all the variations that people like Subaru and Teana use, is mostly because of their personal tastes and capabilities. The only theoretical limit to spell modification, is caster imagination, desire, and capability. Subaru could cast a DB just like Nanoha; it would probably be too difficult or time-consuming to be practical in combat. So she sticks with her version which works for her; one with decent casting speed and power, but sacrificing range.
Gx Hero said:
no they have more skills. Wendi has IS ariel Rave, but can shoot a several types of attacks as seen at the end of strikers during her fight with tena. most are close quarter combat types. It would be like asking signum to find more teqniques that aren't sword techniques. Sein though is questionable being she was meant to be mass produced, no flying and no sign of any other skill poor sein
Wanted to mention that Sein wasn't meant to be mass-produced. There are two types of cyborgs. The most understandable is when you attempt to clone a specific individual to get a specific power, ala cloning Quin to get Nove who can use Wing Road. I believe Uno, Cinque, and Sette are the other three clones produced this way. This isn't as reliable as the other method, only useful if you are aiming to get a specific result.
The other way is using specific sperm and egg and genetic tinkering. This way has a better chance of delivering something viable, but the the skills gained will be random. You can't mass-produce a specific individual with this method, then. Sein's Deep Diver was a really rare and unique skill. You could try the cloning method above, but its more expensive and not as reliable.
I presume Jail would have gone on making the two versions as much as he could, mass-producing mostly unique individuals, only attempting to clone specific individuals much more rarely. But it was partly why he was so interested in Fate and Erio as successes of Project F.