You're making a good point! Regarding the complexity of the task OSRS Gold we deliberately offered diverse training strategies and rewards in order to show Bard's flexibility and how it can be integrated into existing game systems. Was it a bit too excessive? Yeah, probably. There's a chance to go further and said that this design is not by any by any means a prescriptive kind of pitch, so I'm glad you're able see parts of the design you love while others might not be equally as pleasing. It's awesome!
Regarding rewards I'm in agreement with your notion that Bard's rewards aren't as cut and dry as other traditional skill systems. It was a struggle for us to figure out what to put on the rewards menu as far as they go, and it's not unique to our situation because the entire OSRS development team struggle to determine the best rewards for any particular item (looking at Raids 3 rewards). ...)
If the rewards offered are too simple or don't have enough impact Some might ask "what's the reason?" or claim that it's similar to current skills and doesn't take it to a level to justify it as a stand-alone skill. However, if rewards are too complicated or difficult to comprehend, many might argue that it's too far removed from what traditional skills offer, and therefore it should not exist, or be delegated to a minigame or scrapped entirely. The hefty rewards that come from a skill are also a source of a sense of obligation to take part (like Slayer's connection with the rest of your combat skills).
We were keen to avoid the over-reliance on a sense of obligation and the mindset of "I must learn Bard before I go to work on other skills outside of combat or else I'm doing it wrong". The influence was our way of trying to come up with some sort of third-way reward system that doesn't simply give you items or cash in the form of XP gains in other skills. The structures that are in place can cause issues in their own right, and we thought about multiple variations of these ideas, but I'm sure you'll appreciate that it's a difficult balance to strike!
For what it's worth, our expansion methods for Bard Battling and Performing can provide simple rewards, such as raw GP or instruments making, in addition to earning you Influence, which can be used in any manner you want. The Influence system is also dependent on the active participation of Bard for continued access to specific rewards since it runs with a generator-spender-type system however I was expecting it to end up as a difficult pill to swallow for a couple of. It's impossible to know if you aren't trying!
I'm sorry to have you read another dissertation here in the comments, however I do appreciate the thoughtful feedback. I hope other readers will also be able to find the greatest aspects of our design and forge something better from cheap RS gold it.