Good idea, but this makes coupling spells less appealing.As previously suggested, add an additional cost of some sort. Either an amount based upon the number of additional spells, or the level of them are both viable. Or perhaps doubling the cost entirely... Any of these would result in it being an option to mass-swarm or use other nova tactics, it just means that you'll get less bang for your buck and be useless the rest of the day.
Interesting, but not quite sure I get this.
Require some manner of Spellcraft Check to successfully link spells, with the DC increasing for more or more powerful spells. Failure indicates that the whole lot of them fail, yet the power is still expended. Adds the potential for some dramatic situations, allows for routine use of the ability, but dissuades players from gambling large numbers of levels each round.
Interesting, but I'm not too keen on this.Add limitations regarding the type of spells. Perhaps you can't cast the same spell more than once in a round. Perhaps you can't cast spells with opposing energy or alignment descriptors. Perhaps Summoning spells can't be Woven due to the amount of energy used to cast them (and hence the longer casting time). Any of these would add something interesting for players to have to work around. The first suggestion here stops some of the most obvious ploys.