Tier 4: Life-Binder (situational)
Tier 5: Dragon Scales and Life Unbound are both viable
Tier 6: Overprotective (situational)

Psychological Comfort Factors:
1) Unlike many supports, Alexstrasza is able to deal decent poke damage and sometimes harass enemies or even get kills.
2) Can zone out enemies with flame buffet
3) Can take some of the camps and clear creep-waves
4) Dope looks

Psychological Discomfort Factors:
1) No mobility or escape except for the Cleansing Flame (or speed buff from abundance). Can be easily caught when out of position. Can be dived at or nuked down.
2) Poke damage is not enough to suppress most enemies single-handedly
3) Flame buffet is hard to land on high mobility heroes, thus turning Alexstrasza into prey.

Gameplay factors:
1) If Alexstrasza receives damage, her Gift of Life becomes weaker Gift of Life damages Alexstrasza
2) Abundance has long delay and forces allies to group closely
3) No magic armor

1) Using Abundance in the appropriate moment: whether a team is diving or retreating. One can bait teammates into death by using Abundance inappropriately.
2) Chaining Gift of Life into Abundance into Life Unbound (if taken)

Flame Build:
1) Landing Flame Buffet

1) Being in Dragon form reduces the channel time before using cleansing flame.
2) Turning into dragon may evade projectiles.
3) Using cleansing flame to move around the map/clean necessary creep-waves
4) Taking some camps using Flame Buffet
5) Spamming Flame Buffet without missing. Land first on creeps and then try to get enemy heroes through creeps. Flame Buffet --> 2 auto-attacks --> Flame Buffet with stutter-step.
6) Can give timely abundance to give team mates speed buff