Although it's possible to get defensive army defense to over 2,000 it's still not impenetrable and what's the point?
Yeah.... there's players beating 12,000% boost in Guild Battlegrounds. Good luck ever getting stats to a point where no one could ever beat you. Granted that is the outlier, not the norm. But the fact it's possible at all also establishes a minimum required boost to beat those outlier attackers if they're serious about beating your defense.
Defense really is more about minimising losses by reducing the pool of potential attackers rather than removing losses entirely. That's why there's far more value on Aid than there is in Defensive Army stats: Aid guarantee's plunderproofing.
Let's start with the Ritual Flame, only found once a week in the Expedition.
Correction, you can find the Lvl 1 Ritual Flame far more frequently in Relics if you build a Temple of Relics. Granted the Upgrade is still rare, but the base building isn't once you raise up Temple of Relics.
Defensive buildings should be 1.5 times better than attack buildings
Defense Buildings are already more powerful than Attack Buildings at the time of introduction
If we take Ritual Flame as an example. It's Lvl 1 version is 4% per square, it's Lvl 2 version is 6% per square
The Sentinal Outpost (for attacking army) only goes upto 4% on Lvl 2.
4 x 1.5 is 6. So.... Ritual Flame is literally 1.5 times more powerful.
Watchfire has the same stats per square as Ritual Flame so again, 1.5 times more powerful than its counterpart. That being said I can't remember when I last saw Watchfire on offer as a Daily Special during Events. Which either means I haven't been paying attention to it, or it's just that uninteresting to the player base that Inno stopped offering it.
I would have no issue with defending army stats being more readily available. But if they want it to be attractive for a lot of players to pursue they need it to be meaningful.
That means either boosting defending capabilities on the actual army (a second wave for our defending army would help, even if it were just a duplicate of the first wave), or adding secondary benefits to those buildings beyond just defending boosts. The value of defending ties directly into loss mitigation for the vast majority of players because that's the only benefit it has outside of bragging rights.
If Watchfire had Goods, Medals, Forge Points or anything in addition to Defending Boost.... yes it may
technically make it a OP building when it comes game balance, but it'd certainly make it far more attractive than it is now. Which would then make it more likely to be more available, due to people then spending money to obtain it.