Hi Shade3891,
Thanks for your post! 
But I don’t think you should be using those macros.
Re: [nochanneling]
In general, and particularly when latency is high, [nochanneling] is a bad idea as it prevents simultaneous casting, queueing, or clipping of spells. And while Pyroblast has a 4.5 second cast time, it is not a “channeled” spell like a Shadow Priest’s Mind Flay.
Most importantly, Fire Mage is the only class/spec that has a dps rotation that allows (and is greatly improved) by being able to cast while casting other spells (simultaneous casting); [nochanneling] will prevent you from taking advantage of this class/spec ability. Btw, it’s also one of the main reasons why using one (or any)-button Fire Mage macros will always result in considerably lower DPS performance.
Re: /cancelqueuedspell
Rather than /cancelqueuedspell, it’s better to learn how to stop button mashing macros. There are many situations where you need Pyroblast to function, as is. And the benefits of those situations outweighs the occasional and/or accidental hard cast of Pyroblast, which can be easily and quickly interrupted.
For example, if you have Marquee Bindings of the Sun King, your playstyle and rotation using Pyroblast will change. You’ll want to hard cast Pyroblast after an instant cast (hot streak) Pyroblast.
Re: “prevents blasting the 2nd charge of Fire Blast”
Again, the best solution for this is to learn how to stop button mashing macros. Fire Mages are a reactive class/spec that uses Fireblast as a high priority spell in its DPS rotation. Fireblast should not be limited in any way, even when using macros to allow for lazier play during quests, dungeons, or lfr. (To be clear, I don’t think lazy macros should be used in “current” normal, heroic, or mythic raids.)
Also, using spells like Slow Fall in a /castsequence to prevent accidental use of the 2nd charge is a terrible idea because Slow Fall has a 1.5 second Global Cooldown. Even if you were able to lower the GCD with Haste, it’ll result in a significant DPS loss.