Point by point,
The problem here should be easy to identify: the tools are, at best, a side-grade from iron, while taking more resources to craft (including iron, in the case of silver alloy tools) and having lower durability.
They would need to either be cheaper, more durable, or have higher base damage in addition to the benefits of being swift / having higher critical damage. The investment part is really key here. In the case of hammers, for example, using an iron hammer results in enough iron to replace it, plus some. Using alloy tools, this is much more difficult to achieve, regardless of planetary tier.
They’re also, somewhat unexpectedly, worse in terms of forging effectiveness than iron, making iron tools better even for use in the forge.
Again the issue here is the compounding investment in making a titanium tool. You need to mine and smelt iron/copper, gold/silver and titanium, then craft precious metal alloys, then craft titanium alloy, to finally be able to craft the tool.
For gem tools, you need fewer crafting steps, and less variety of resources. You just need the gems, which are compacted, and then refined, and you’re good to go.
A compounding factor is that there are too many competing uses for alloys in Power Coil crafting, particularly Advanced ones: you need a VERY LARGE quantity of precious alloys (for machined blocks and to make titanium alloy for the furnace bases) and, of course, the titanium alloy itself, while using barely more gems per Coil than per tool.
So, in the end, gems are more plentiful, comparatively, than titanium alloy (or gold/silver alloy) for tool making, as they’re used in fewer recipes.
Edit: A possible solution would be to make furnace pieces and compacted/refined/machined blocks use bars, rather than alloys. I’m sure I’m not the only one with an over-abundance of titanium bars and not enough precious alloys to convert 'em into something useful, so they just sit there being pointless.
The issue here (in my opinion) is more of an initial lack of definition for what role bombs were supposed to have. Are they for combat? For buffing? For mining? For clearing out terrain?
Personally, it always made sense to me that they should be used as terrain destruction/removal, rather than as Seam Detectors, in mining, and as an Area of Effect buff/debuff delivery system in combat, rather than for damage.
However, too much time passed with them being allowed to be used as Seam/Ore Detectors, without any indication by the develpment team that this was not their intended use, so they came to be expected to fill that role, and when they were properly defined without warning as a terrain removal tool, which makes sense for bombs, it came as a bit of a shock to the people that believed (and still believe) that their intended use should be as ore revealing tools. Better communication, and a better job in defining the role that items are expected to fill, would go a long way towards making the balance discussion more productive. Particularly in the case of bombs, that still sit somewhat undefined in players minds despite the 199 patch seemingly clarifying their role as a terrain destruction tool rather than an ore revealing tool.
This point was fairly well argued on other posts in this thread, so I’ll just add that a significant part of the issue comes from diamond being found in a particularly desirable resource band (together with gold, titanium, hard coal and medium coal, as a rule) while various other gems are found in comparatively poorer areas in terms of highly desirable resources.
I believe the issue lies more in the rewards than in the risk and time investment. The effort-reward ratio is skewed towards the easier meteors, and I believe that to bring the higher level ones in line the solution would be to increase the rewards rather than change the effort part of the equation.
