Flash Tome

[Problamatico]

[Dramatic Crossroad]

imo text should be something like:

"Activate only during your opponent's Main Phase, also it cannot be activated in response to your opponent's card and/or effect; Immediately after this effect resolves, activate 1 Normal Spell from your hand."
 
I think it can be broken, even if you're going minus 1, also in order to be functional it kinda needs to be Chain link 1 and resolve last, otherwise you'll have a normal spell with its cost/ignition trying to play in the middle of a chain, giving your opponent no opportunity to respond to it.
Might also be interesting, but... would probably break the game. Some, if not all, Normal Spells put into consideration the fact they are spell speed 1 and many have built-in downsides that only work during your turn (like being unable to Special Summon or skipping your Battle Phase).