Getting a 2nd AO at a small footprint has massive potential. Although it heavily depends on how much % chance it offers at lvl10. Since it continues with 0,16%/level and is capped at 25%. For reference AO increases its chances by 0,16% around lvl159 and offers than a chance over 45%. Although it does seems to not improve between levels 156 and 157. Assuming the Space Hub AO to hit 5% at lvl10 it would take till lvl135 to hit the cap of 25%. Assuming it is higher and offers 10% at lvl10 it would hit its cap at lvl 94 (rounded). AO offers at lvl10 6,98%. So, if it does offer 5% at lvl10 it's mildly underwhelming but offering 10% at lvl10 is unlikely, very high and the final leg would be an improvement less than 0,16%. Which is implied that it wouldn't. So, my guess is between lvl94 and lvl135 with a greater likelihood to lvl135 to find the cap of 25%.

As a stand alone GB it's too expensive and offering insufficient crit. hit chance to be interesting. However if the competitive GbG meta shifts more in favour of AO, which is speculative but what I'm expecting, it'll become a vastly more interesting GB. Alongside the SA:SH Alca. Let's assume lvl180 AO's become common within top guilds. Offering ~48% crit. hit chance. Assuming my estimate is correct for the SA:SH AO of 5% at lvl10, this will offer in combination with a lvl180 AO:

~53%, ~60%, ~65% at SA:SH levels: 10, 54, ~86 respectively

Imo lvl54 would be already an outstanding achievement. Considering massive costs are to be expected. So, a crit. hit chance around 60% could become common within top guilds. Considering AO lvl201 offers 50% crit. hit chance it's quite a step up. Definitely not a game changer for intermediate players but highly developed and competitive players that ~12% extra crit. hit chance in combination with a lvl180 AO and 45% keen eye can prove to be significant. This is still with the assumption that there ain't no major bottlenecks we don't know about yet before lvl54 of the SA:SH AO.