Aligning.
I don't think the "also 中国 dial." note is helpful.

@@ -9 +9 @@
-<xref type="see" seq="1000730">行けない・いけない・1</xref>
+<xref type="see" seq="1000730">いけない・1</xref>
@@ -11 +11 @@
-<s_inf>also 中国 dial.</s_inf>
+<gloss>bad</gloss>
@@ -13,2 +13 @@
-<gloss>not good</gloss>
-<gloss>of no use</gloss>
+<gloss>naughty</gloss>
@@ -18 +16,0 @@
-<xref type="see" seq="1000730">行けない・いけない・2</xref>
@@ -20,2 +18,4 @@
-<gloss>hopeless</gloss>
-<gloss>past hope</gloss>
+<s_inf>after the -te form of a verb or adjective</s_inf>
+<gloss>must not (do, be)</gloss>
+<gloss>should not</gloss>
+<gloss>ought not to</gloss>
@@ -25 +24,0 @@
-<xref type="see" seq="1000730">行けない・いけない・3</xref>
@@ -27 +26,22 @@
-<gloss>must not do</gloss>
+<gloss>useless</gloss>
+<gloss>no good</gloss>
+<gloss>bad</gloss>
+</sense>
+<sense>
+<pos>&exp;</pos>
+<misc>&col;</misc>
+<gloss>hopeless</gloss>
+<gloss>beyond hope</gloss>
+</sense>
+<sense>
+<pos>&exp;</pos>
+<misc>&col;</misc>
+<s_inf>used to express sympathy</s_inf>
+<gloss>unfortunate</gloss>
+<gloss>a shame</gloss>
+<gloss>a pity</gloss>
+</sense>
+<sense>
+<pos>&exp;</pos>
+<misc>&col;</misc>
+<gloss>unable to drink (alcohol)</gloss>

I'll make them "col" instead.
As for "せん" it could be an entry. It's not in any ref that I can see. I think it's too much of an outlier to go in the conjugation table.

@@ -10,1 +10,1 @@
-<misc>&arch;</misc>
+<misc>&col;</misc>
@@ -19,1 +19,1 @@
-<misc>&arch;</misc>
+<misc>&col;</misc>
@@ -26,1 +26,1 @@
-<misc>&arch;</misc>
+<misc>&col;</misc>

These meanings are all listed as archaisms, but I wonder if that's correct. ”いけん” is also used as a conversational form of いけない -- from what I can tell, used only when talking to one's social inferiors, and mostly by men. But it's more of a verb form than a word and applies to all verbs (e.g., できん for できない) so I don't know if it should appear as a meaning.  On a related note, I came to this entry as I was trying to find a definition of せん, which it turns out is that conversational (superior, masculine) form of しない -- I'd not seen that before (私の名前など気にせんでいい - never mind what my name is).  Again, though, I don't know if it merits its own entry because it's just a verb form (although one that is not included in the verb conjugation table for する).  But from a user point of view, it would have been nice to find it in the JMDICT :-) Perhaps it is something that could be added to the verb conjugation table instead?